1) To enter into an arena and get your groove on.
2) To seduce a girl with your presence and your oozing charisma.
3) The physical act of taking off your coat or over garment and placing it on the floor; being sure not to contravene any health and safety regulations.
2) That girl was all over me, that's what happens when I lay the mack down.
3) I came in to the room, found an appropriate spot and thought this is where I shall lay the mack down.