If you can't figure that out, then you just need to say nothing at all. Keep it to yourself. It is not something easily explained, playful ribbing is a bit ambiguous. There are also things better said verbally and/or with body language, since text it to be taken as written (ever wonder why comedians do stand-up instead of writing books?). It can be very difficult to understand the context.
Cursing can be fine, if you know how to use it. If you don't, then do not curse.
Playful taunts such as the taunts in-game give a sufficient idea on how to communicate with your opponent. That is why taunts are there, if you can't think of what to say. Play the FULL taunt, don't spam it. I miss the days of League of Legends when opponents actually used the in-game taunts. Family friendly entertainment with competitive interactions will sometimes have fun stuff to say that don't negatively target your opponent.
Learn respect. If you you don't have respect, you will never learn how to be playful with your opponent.
And no Kefka levels of monologue either.