It’s likely they had strong genital dysphoria or other issues surrounding their penis. Most people don’t have the desire to cut off their penis, mushrooms or no mushrooms. I’ve had friends with bad dysphoria who did it, no mushrooms needed, but I can imagine someone also doing it while they’re high.
I don’t think it’s likely unless you have really bad penis dysphoria already, believe me, you’ll know if you do. Though your egg cracking on a trip is still possible even if you don’t hate your penis, and that can be scary and uncomfortable. IMO best to do it while not tripping.