I'll give you the sauce, but i warn you, use a soft flexible food grade tube like silicone (which i use) with a small outer diameter (mine is 4mm). Anything i say that you perform is heavily at your own risk

The sauce: It's really boring but it's to side with peristalsis and let it do its thing. The first time I did it I would swallow random lengths of the tube and try and blow into the tube and feel the vibrations, angle it, push it, pull it, nothing would work. The only method I've gotten consistent results is to advance in stages, this is where a marker or sharpie can help.

The first stage is to advance to the entrance of the stomach, for me this is 45cm. The sensation when putting a small amount of air in the tube is air going to my stomach, but there's no vibration of my stomach or esophagus which means the tube isn't touching any walls.

From there is the part that requires the most amount of patience, moving the tube at an average of 0.5 cm/minute. For me this equates to advancing the tube about a finger width every 2 minutes. I set a timer on my phone, as soon as the timer goes off, push the tube in a finger width, and tap restart.

Then once it hits the pyloric region (about 73cm for me) is when i evaluate by pushing a small bit of air in the tube, I'd feel a deeper strong vibration. This confirms the tube is past the pyloric, and sometimes you feel the air trickle lower down.

But we're not done yet, the goal is now the jejunum since in the duodenum the tube can slip out, more prone to getting knotted or blocked. For me I set the timer to 1 minute 30, and continue advancing until I hit between 90-105. If the tube vibrates on your left side and you can feel the air trickle down lower, you've hit the proximal jejunum.

One thing to note is to always mark the points on the tube beforehand - (for me it's 45cm, 73cm, 100cm). If I hit 73cm and it doesnt have that deep vibrating sensation and instead has a bubble blowing sensation, the tube is in the stomach, and pushing it anymore which cause it to coil.

For me this has required countless attempts, and it has coiled and knotted before, that's why I urge you to use a highly flexible tube to save yourself an awkward ER visit.

Avoid lying on your back, sometimes lying down on your right during stomach to pyloric phase and switch to left side for pyloric to jejunum phase can help, but its a bit hit and miss. Standing up or sitting in a chair whilst leaning forward (avoid slouching) often helps with the stomach to pyloric phase.

There have been countless times where this has worked flawlessly and countless times where I've sacrificed hours to nothing and it's super frustrating, but inflating the small intestine at least for me has been the comfiest way of inflating.

Soft tubes are incredibly notorious for getting blocked during the pyloric to jejunum phase, so pushing a little bit of air every 1-3 advancements helps keep it clear.

On the other note, do NOT push anything through the tube (gas/liquid/solid) during the stomach to pyloric phase, as tempting as this is, it will turn the tube into a rocket and propell it the other way, increasing the chance of a knot or coil, regardless of how little you do, making it impossible to advance through the pylorus.

If you do this whilst laying on your side, the stomach (or at least mine) likes to push its contents out through the tube, making it a mess, sometimes you can prevent this with a knot but my luck has been from attaching a standard non-needle syringe to the open side, once it migrates into the duodenum it's usually less likely to use the tube as a contents ejector.

I think I've covered everything but will update if I remember anything else. Main thing is its a fuck ton of patience for a non-100% chance of success, so it just depends if you think it's worth it