"Keep sucking it"

I reply, and smile at Millie.

Millie leans on my leg and looks up at me and smiles for a while, but Patti does not waste any time and dives straight down on my cock again and her head starts moving up and down.

Millie looks at her older sister working my cock with her mouth for a while, her fingers tickling my balls, and then she says:

"Stand up, I think you are going to like what is next."

I slowly start to stand up. Patti does not move my cock out of her mouth, instead she keeps her mouth on it as I am moving, so when I am finished standing up she is on her knees in front of me, my cock never having left her mouth.

Behind me, I feel Millie standing with her big tits rubbing against my back, and she moves downwards slowly, her big tits sliding along my back. Then, when she has finished dropping to her knees, she starts kissing my lower back, then moved her mouth and tongue downwards until I feel her starting to rim me.

The sensation of Millie's tongue on my ass is a surprise at first, but in combination with Patti's mouth on my cock it feels incredible. I know I am not going to last long now.