This term is for when
something/
someone you desire is not directly
available to you, and you want it.
Hot girl walks by you and her ass is just screaming for you, you might say to your
friend next to you while you watch her walk away, "Lemme get that
butthole!"
Your
friend comes over with a 6-pack of beers and your thirst is not quenched, you might say, "Hey dawg, you brought some beers! Lemme get!"