usually guy who after urined will just stuck in the underwear so it's unhygenic. These guys could not care less whether it smell later or not, cos they are not bother with it.
As for your bf, ask him to practise cleaning up his didi after use for sometime..probably it gets better, else something is not right..better dont touch his didi..as suggested use DETTOL !!

Some guys think it's too faminine to do so..well all I can say, those are dirty guys who dont bother what hygiene means whether it's cut or uncut.