Juice (specifically a gallon of Hawaiian Punch) that is purchased and left in the trunk of your car over a period of time for consumption.
On my road trips i never to have to buy anything to drink because i always have my Trunk Juice.
Ejaculation in a girl's ass, or reference to performing anal sex with a female.
Did you serve her the Trunk Juice?
I took her home and put some Trunk Juice in her.