Have you tried different positions? Some girls might just get bored after awhile with you just sitting the same way there, and grunting.
Maybe stuff her panties up her muffler till she squeels.
Maybe check your petcock and see that it isn't dripping.
Maybe just lay there and listen to her dreams.
Maybe buy her some flowers.
Maybe order up some of those male growth pills.
Maybe introduce her to another naughty moped and take turns on them.
Maybe move to a part of the country where she sees you as a man.