stealing bases

When you skip over one of the bases. The bases being the 4 F's. French, Feel, Finger, Fuck.

Brian and his girlfriend Ally stole first base, and began feeling and fingering before they even frenched. This was Brian's favorite thing, stealing bases.

stealing a base

When you take the next step(base) in a relationship without consent.

Did you hear about Jesse and Chloe?
Yeah, I think she dumped him after he tried stealing a base.
That’s rough.