Progasm and small build

After reading about all the dry orgasm/super-o , I ordered a progasm myself as i’m not new to anal stuff.

I’m not sure if due to my small build 5″5 that i’m unable to keep the progasm fully inserted / keeping the k tab pressing against me. I felt good sensations and occasionally I will have 1 (ONE) strong semi voluntary and some involuntary that suck the progasm really in and then that’s it….most of the time it just didn’t go far enough to press the k tab against me.

Also a quick google showed images of how smaller aneros is fitted within the ass and various google searches yielded sites that say the prostate is 2-3inch inside. (Just google image search aneros prostate)

So question is if the progasm has 4.2 inch insertable, wouldn’t it be too long and instead of pressing against my prostate, the head will be pressing against some other parts?