Diagonal nosing is the act of inserting your nose into a woman's belly button, whether sexual or non-sexual is irrelevant.
"Hey, bro, did you hear what Max did to Cait?"
"No, man, what happened?"
"He diagonal nosed her, dude."
"Oh, dang, bro, I didn't know she was into diagonal nosing."
diagonal nosing is the act of inserting your nose into a woman's belly button, whether sexual or non-sexual is irrelevant.
Can be a serious moment or just a laughable act.
"Hey, bro, did you hear what Max did to Cait?"
"No, man, what did he do?"
"He shoved his nose into her bellybutton! He diagonal nosed her, bro!"
"Ah, dang, dude, I didn't know she was into diagonal nosing."