Last longer during oral?

[lalala]

My current girlfriend and I are currently unable to do the dirty, so what the usual cycle of goofing off that occurs is she loves to dry hump for about an hour, very extended period of time, and I work my magic on her. Then it comes to her taking care of me, and my privates tired after that much work, and just wants to get things over with. She says she doesnt care, but I would like it better if it lasted more than 4 minutes. Just embarrasses me