That's awesome you're getting hard! Between eating her out and enjoying the sweet taste of her pussy (it really does taste amazing), and licking/fingering her cute tight asshole, there is so much to do! Gotta pace yourself or...
That got my dick hard! When she face sits on me, her thick pussy lips are to die for!!!! Mmmmmm! Sometimes she will also slide forward a bit more so your tongue brushes her asshole! I get so hard!!!