Well for me, my type of PE would be where a guy accident spilled chemicals on him but turns out fine. but when he gets aroused it would get longer and thicker. and his erection accident would be with the girl he likes. He'd think it's a normal erection but then realized his pants are getting tighter. He's trying to remain calm and collected so the girl of his dreams doesn't expect anything. BUT the erection is to uncomfortable for him and the pants rip. The penis is so sensitive now that he erupts right there! The girl is disturbed and turned on at the same. She realizes as well that her boobs are growing as well(cause some of it went in her mouth) and her shirt is getting damp, finding out she's lactating! They confess...and they go out for a few months and then they do it.
Yeah...that's how I picture it