1. (verb) Is a reference to the beer tap and refers to the act of intercourse without the extra baggage of a relationship. Someone taps a "piece of ass" for sex until they are all used up and/or dry. The tapper must then venture out and forage for another person to "tap". Thence whatever relationship the previous tap had with said tapper is null and void. The act of tapping hearkens back to a much simpler more animalistic time in our history when women were plentiful and had higher infant mortality rates.
The movie "Animal House" is said to have spawned this etymological phenomenon.
1. I dare say, I would amply enjoy tapping that ass given the appropriate opportunity.