Refers to Heroin, since Bruce Willis and Demi Moore were both shot the fuck out on heroin back in the day when they were a couple.
Also lyrics used my Interstate Fatz, a white freestlye rap artist from Eastside Las Vegas, also a blood gang member
"used to maneuver white but now I'm out here moving Bruce's Wife"
"Cherry laces, grenadine shoes, just sent 10 balloons to the visiting room"