Junpei's working theory is that having the fucking coitus on a Tuesday was a similarity that led him to believe that it was you, I think.

And as far as I know, Wukiri doesn't share his bed with that many people. He's always so offended when I ask to make sure he's safe for the week. He said 'I get that out of the way as soon as possible...!'

I guessed that he must have done it with you, since you're already sharing a room.