Nipple pocket

A small shirt pocket. Usually located in the nipple area.

OwO: Hey dude could I borrow a pen or something?
UwU: I don't have a pen on me, sorry.
OwO: But you've one in your nipple pocket!
UwU: Oh, right! I forgot about it since I couldn't see it. Here you go!
OwO: Thanks, UwU!
UwU: No problem mate!