Most of us are in the UK so our acronyms aren't the same as in other countries like the US.
OW/OWO = Oral With a condom or Oral Without a condom
CIM = Cum in Mouth
RO = Receiving or Reverse Oral (oral sex on a woman)
BB = Bareback (vaginal or anal sex without a condom)
A-levels = Anal sex
GFE = Girlfriend Experience. That is, with kissing and behaving as if you're his girlfriend
PSE = Porn Star Experience. Less cuddling, more moaning. Often involving more anal, deep throat, etc.
DT= Deep Throat