If male kobolds, dragonborns, and lizardfolks possessed a sheath, genital slit, or anatomical structure similar to that of humans, what would be the sensation experienced during an erection and how sensitive would it be from base to tip?.

Bruh. You already made this thread. In fact, I'm pretty sure you did it multiple times.

Regardless, all those things are fictional, meaning their dicks are, too. You can write your exact character having the exact kind of genitalia you like most there is no "correct" kind.