Under the water, they were nude. His trunks at his thighs. Her bottom, floating away in the current, lost to the deep. The weightless sensation of surrender, floating in the water, her legs spread. 

His thick cock deep inside her. She in her inner-tube, he was in his, joined below the waterline. Her back to the lake and his to the shore so her husband could not see. Completely lost in her third orgasm, it had been so long since she felt like this.

“Fuck, baby, you feel good. Cum for me.” 
“Soon. I want this to last awhile, Mom.”