Mostly used as a substitue to sexual descriptions, it can also serve to shorten or skip over parts of conversations. It allows the listener to fill in the blanks themselves with their imagination.
The phrase was used recently as a lyric in an Urban Hip-Hop Song; "Holidae In".
Chingy: "One thing leadin to anotha, let the party begin!"
"Well, me and my girlfriend were watching a movie, and..... one thing led to another and now I've got child support for triplets"
When a group of co-workers go to the local bar for 1 drink after a long work day. One and done's usually involve trash talking and extremely inappropriate conversations that make other people at the bar feel uncomfortable. It is very common that the participants of one and done will have more than just one drink. However, the term was created to make people feel better about their life choices