That “wall” you’re hitting is the juncture between the rectum and the sigmoid colon. There’s a sharp turn and a minor sphincter muscle there, which prevents fecal matter from continually moving down into the rectum.

In order to pass that barrier, you need four things.

1. Plenty of lube in the rectum so the juncture is slick.
2. A dildo with a tip that isn’t too blunt, so it can gently open the sphincter.
3. A dildo that isn’t too stiff, so it can bend to make the turn.
4. Patience.

Once you have the tip positioned at the juncture, try turning it back and forth until you feel it go in just a bit deeper. That will let you know you have it lined up optimally for the turn. Once you have the sweet spot, gently turning it back and forth a few degrees will help work it in. Don’t be afraid to move it in and out just a little bit while turning it. You’re trying to coax it open, not ram it open.

Keep in mind a smaller diameter dildo will be a lot easier to get past the barrier u til you have it trained for larger ones. You may feel some discomfort once you get up in there, but just holding still and deep breathing will help it to pass so you can keep going further. Be mindful that discomfort doesn’t mean pain. If you feel any sharp pains, stop and back out gently. Play for a while in known territory and relax, then try again, maybe with the dildo rotated 180 degrees to see of that helps.

Good luck!