Dennis lay on the floor, the sheer volume of mortification coursing through his veins keeping him immobile. It wasn't the fact that he'd caught them having sex, or that they were having sex at all that mortified him. Nor was it because they were naked - he was supremely unperturbed by both his own and other people's nudity. It was because he had been that guy who'd walked in on his friends going at it instead of assuming that they would very logically be going at it. Although admittedly the open door did stand in his defence.
"Nnnrfghgh," he mumbled as they both sat down next to him. After several moments the ability to speak returned to him. "I can go and, I don't know modify my memory and drown myself in the shower if you two want to finish," he said at last. He opened his fingers slightly and looked at them with the ghost of a grin. "Although really, you were both going at it full tilt. Aren't you meant to have a limp, Rolfie?"