(NSFW) Question about anatomy

So when I'm reading PIV (penis in vagina) smut, sometimes during penetration when the character with a penis is hung they say you can see a bulge on the other person's tummy. As someone who has never had sex with a penis-haver (or a dildo) before: does that really happen???? Can you see a bulge?? And if/when it happens, does it hurt?

Bc 99% of the time on those same fics they describe the penis hitting the cervix as something pleasurable (which I've heard it's not for the majority of ppl) so I have doubts on which parts are real and which are not 😭

Sorry for the TMI and if it's a silly question, I didn't know where else to ask, and since I see it a lot in fics I figured I'd try my hand here!