Ok not to sound weird but it’s a genuine question about kirishimas quirk

so we all know that kirishimas quirk is hardening right? And he can make his entire body hard, but is it just his main body parts or is it everything including the places where the sun doesn’t shine? like I know that this is super inappropriate but this is a question that has been bugging me since I started watching it. I’m sorry if this sounds really weird but i feel like its a question that everyone in the fandom has probably wondered.