Sexual activity, more specifically the act of placing one's body part ("candy") into any of a partner's body parts ("bag"). Getting action; of a sexual nature. Scoring.
see also: bulk candy.
"Dude, did you bag any candy last night?"
"I am sooo gonna candy-bag with LaFawnda tonight!"
Joe: "What are you doin' right now man?"
Damian: "Yo, I'm candy-baggin'. Call me back later."