to search for something (such as private or hidden information) in usually a quiet or secret way
She caught him nosing around in her papers/office.
A sex act involving 3 people. One person has their nose in another persons butt while the first person is having sex doggy style with another person. One of said persons is reaching around and putting their own finger in their own butt.
Ryan, Becky and Lisa performed a “Rudolf the brown-nosed reach around” last night.