Prefer it to be a bad guy, but a dark version of Foggy, Karen or Claire would be fine too. Someone captures Matt, maybe ties him down or drugs him so he can't get away, and then they force him to cum again and again against his will. Reason is entirely up to you, I just want to see him helpless, senses gone haywire from the constant unrelenting stimulation. It could even be a form of torture, you know, "tell me what I want to know of I'll do it again," that kind of thing, or it might just be for their evil enjoyment.