The Brief: Creepin' refers to stalking someone's social media, or creeping around.
Creepin’ or creeping is often done to an ex. The term can also refer to old-fashioned stalking or following.
It can also be used to refer to a more traditional and general method of creeping, as in moving, going, or sneaking around. The term is used in songs by artists including Childish Gambino, Drake, and Travis Scott.
Who’s that creeping through my window? – Travis Scott, “5% Tint”