From Longman Dictionary of Contemporary Englisha bit of rougha bit of roughBritish English informal someone of a lower social class that someone has a sexual relationship with – used humorously → bita bit of rougha bit of roughBritish English informalSEX/HAVE SEX WITH someone from a lower social class than you, with whom you have a sexual relationship → rough
Examples from the Corpus
a bit of rough• At the moment it looks more like a bit of rough pasture ... full of dandelions and clover patches. 