You don't spam the button, you hold it down.
Some sequences you can't shake off. Child birth is one of them. Futa phantoms is not.
yeah, I get that. when I said "buck" I meant "force off of me successfully via the struggle mechanic." I can get the phantoms off of me, but only one at a time and they keep spawning back in.
the child birth sequence continued directly into it mounting me and never loaded the ability to struggle out of it. I only let it happen the one time (as getting soft locked until I give up and die was rather unfun), but I can test for repeatability if you like.
I'm on .37 btw. beat it. got the "cheat mode." so it's not game-breaking or anything. just less fun.
Edit: looks like it was a glitch, instead of a full bug. just tested it.
I WAS able to buck it this time, but it still didn't load the health bar like everything else does. took over 80 points of damage too. (had to hit it again) nevermind. it has an "end of scene" that's supposed to finish and then disappear. (tested it a couple more times.) so the "finish animation" never loaded for me on that first run.