keep falling off the swing because of muscle relaxing

first off, i think i'm getting somewhere... since yesterday i gotten a spike of pleasure...although it was through a very different process than the described swing. Also the spike is such that i know there is more behind that spike.

anyway back to the question. I've found the swing that was being talked about. However, when on the swing, i keep falling off... half way through some muscle i don't control decides to relax and when that happens i cannot find the spot that generates the p-waves (if those are p-waves i feel).

It's definitely a muscle i don't control because my sphincter might be contracted and the muscle that relaxes just makes it feel like that whole region moves outwards (i.e. the aneros and the sphincter move a little bit outwards, maybe a cm orso?)

first of all, does this make sense? if so, what do i do, because i'm not finding the sweet spot anymore and this cannot ride the swing to higher heights.