Good afterglows come from good sexin', period. The kind of rough, get it off sex that leaves you sweaty and in a heap on the bed and the two of you just lay there for minutes at a time because every muscle in your body is utterly spent. (That said, I had a great fuck before work, and I think everybody could tell I just got laid. All smiles and my hair was all curly and shiney and wonderful, hahaha.)
I don't think the condom has anything to do with it.