SMS short for "Biting My Finger"
can be used at varying intervals in an online chat between former paramours and the subject of prior encounters along with the faint suggestion of potential future engagements is broached especially likely when the subject of skill/performance improvement underscores the conversation
x: Rematch? I might be up for it.
y: Name the time/place
x: How are you, anyway?
y: Better, I assure you, in all matters.