Haven't seen much in the way of a DIY home guide though. I'm an AB at heart with a fondness for bondage so my thing is being restrained and force fed my formula. Getting it all setup took lots of trial/error and experimenting but I'm really happy with my setup. It's cheap, easy to make, and it works. So here's my guide for force feeding liquids SB style.
First thing... safety. Just in case you missed it... SAFETY. Ok, let's be realistic for a moment. There is absolutely no way to 100% force feed yourself something during self-bondage without it being a major safety risk. Whatever setup you use, there has to be some part of the design that will let you escape from drinking whatever it is. Which kind of defeats the purpose/idea of "force feeding" right? Well almost....
The catch is leaving yourself some way out where there is some sort of "dire consequence." The idea being: you CAN get out of drinking the liquid but there'd be an immediate penalty that will entice you not to. For example, when I first started using this method I was forcing myself to drink grape juice as a punishment (I despise grape juice... long story). Anyway, my system forces the liquid into your mouth, but you don't have to actually swallow it. So you could just let it drain out of your mouth making a mess. Since the mess wasn't "enticement" enough for me, I would use one of my best white shirts as a bib. Now if I didn't drink it I would ruin an expensive shirt. If the simple mess of having your liquid of choice dumped everywhere isn't enough, be creative. If you have the self-disipline you can punish yourself later so you don't have to have an immediate consequence.
Ok... onto the actual setup:
** 1/4" vinyl tubing , 1/2" works too but nothing larger (at least 10-20') Lowes/Homedepot ~$3
** Quick Connect Couplings (at least 2) Lowes/Homedepot ~$2
** Pepsi Bottle 24oz or whatever size you want (you can't use Coke because I like pepsi better)
** Hot Glue
** Drill with 1/8" and a bit the size of your tube
** Some type of gag that you can fit the tubbing into. (I use a pacifier)
** Waterpik (optional); This is a type of water pump you can find in the dental section of most major chain stores. Its use will be described later.
Drill two holes into the Pepsi bottle (you did get Pepsi, right?) using your two bits (1 hole for each size). You will feed 1 end of the tubing into the big hole, the smaller one is to allow air to pass through (explained later). Once you have the tubing all the way to the bottom of the bottle, hot glue the top to cover any other air holes (leave the 1/8" one open) and to secure the tubing it in place. Cut off the tubing about 6" from the cap and attach one of the Couplings.
Attach another end of tubing to your gag. For the ABs out there, I used the largest nuk I could find in a store (and if you have one of those adult size nuk 5s you can use that). I remove the ring (yes, you have to break it off). Pull out everything so you're left with the nipple and the mouth shield. Insert your tube and use LOTS of hot glue to seal the nipple to the shield and to secure the tube/cover holes. Don't leave any spot where air can get into the nipple. Now using some small sissors or a hot needle, make 3 small holes at the bottom of the nipple. I cut mine at 8,6,4 o'clock. 6 being the very tip. ( you cut 3 so that you can't block 1 with your tounge). Leave about 2-4' of tubing coming out then cut and attach another coupling. Then take some elastic and tie two pieces, 1 around the back of your next, the other around the top of your head. The idea is to have something to hold the pacifier in your mouth.
You're left with: A Gag w/ tubing attached, A bottle (pepsi right?) w/ Tubing, and extra tubing.
Setting up your Scene:
Secure the bottle somewhere about 1-2' above you. Attach the extra tubing (should be about 8-10') to the bottle's coupling. The bottle sits top side up (just like it were on a table/surface) and the tubing comes right out the top and the immediately downward towards you. You can wrap it around something as long as most of it is below the bottle and above you. Insert your gag and attach the other end of the tubing to your gag. Go ahead and restrain yourself in whatever fashion you'd like (please don't lie down... make sure you're proped up at least 30-45 deg). TaDa! In short time, you will be force fed!
As you breath and/or suck on your gag, you are removing air from the tubing. Before too long, your liquid will get in the tubing and start heading for your gag. Once that happens, physics takes over. This is called "siphoning". From this point on, the liquid will keep draining into your gag until it's all gone.
Again, it's not fast enough to FORCE you to drink it. You can always just let it drain out your mouth. But there's no stopping it from getting there.
Adding Some Spice!
Remember I mentioned the waterpik? Well sometimes Physics is just too slow, or after awhile, you learn to just not breath in on the gag. So that's when I introduced the Waterpik and boy did it have some fun uses. This is basically a water pump that you can attach to the 1/4" tubing. Set it up on a wall timer while you're restrained and once it's on, it'll pump the liquid into the tubing. Same results as before, it'll go in your mouth but you don't have to swallow. This is my current setup of choice. I'm restrained to my chair, gaged, and the waterpik is loaded with my forumlas. 15 minutes in, a wall timer starts the pump for 2 minutes. I'm forced to drink it (or make a huge mess and be punished later). 15 minutes after that my key release triggers. Simple 30 minutes of forced feeding. Well actually 28 minutes of sitting and waiting and 2 minutes of eating hehe.
This is where it got really fun! Get a T-Coupling. This will allow you to attach two sources of liquid to your gag. For example, I put Formula in the waterpik and Pediasure in my Pepsi bottle (about 25oz combined). Now interesting things happen. If I'm not careful I'll suck on my pacifier too much and drink the sweet Pediasure early... meaning once the pump starts I'll be stuck with the taste of formula in my mouth until I'm released. If I don't drink it, the pump will start anyway and I'll first have to drink the formula and then immediately after that (the pump will trigger the siphoning) the pediasure. This has some interesting combinations.
For example my grape juice. I'll put water in the pump and grape juice in the bottle. Now I really really really don't want to suck on that pacifier and drink the grape juice unless I get the water right after it. So I have to try and time it right. If I drink too early I'm stuck with that godawful taste in my mouth until the pump starts. If I don't drink it soon enough however, the pump will start, I'll get the water first, and then followed by the grape juice from the bottle (remember the pump WILL start the siphoning of the bottle) and there again I'm stuck with the grape juice taste. This has been really fun being restrained for 90 minutes w/ the pump turning on 30min in. I always get paranoid I'll be stuck with the grape juice taste for 60 minutes and end up drinking it 5-10 minutes in. Though a few times I've been squeamish and waited too long. Then I hear the pump turn on, I haven't drank the grape juice, and I think... "Oh crap." I'm forced to drink all the water and then right after that... there comes the grape juice.... what fun!
This has lots of different variations and combinations. Experiment... have fun... or well, have a good experience hehe.
And remember... SAFETY!!!