Come from behind

Ducking behind Fen, you use a rear waist lock to hold her down. She tries to buck you off, the thug hates being on the bottom. You successfully keep her off balance however. She goes down on her belly with you on her back. You feel every hard curve of her rock hard torso, & your dick slide between her ass.

"Hrr! Get your cock away from me!"

"He he, no way bitch, no wa...."

Somebody (the masked stranger, of course) grabs you by the ankles & pulls you off of Fen. At least she tries to. You cling to her waist for dear life. Ironically, this serves as a bearhug which makes the thug groan in pain.

Thanks for the idea, you interloping idiot.

But it can't last for long. Sweat & fatigue mean you wont be able to hold on for long. & Stranger has all the energy in the world left.