There is no doubt in my mind that Grayson was drugged. Consider that he only had 2 beers. He wanted to screen, but somehow no sound came out. He wanted to say no, but couldn't. Need I say more?
Now, what was that question about consent? At what point was consent revoked due to being drugged?
Quite frankly, Grayson was lucky that the anal tears were minimal. Likely due to being stretched by Mike in the first place.
Oh, and the blood stain won't come out. It's been too long and has set. If'n ya ain't used to doing laundry, ya ain't gonna know this.