Muzan got irritated of you two laughing together while he was doing his research for the blue spider lilly. He got mad and snapped out

'SHUT IT YOU TWO!'

You both didn't got scared or shocked, you were laughing.

'THATS IT.'

Muzan grabbed you two and dragged you both to a private room. The other one was watching in horror and you were suffering. Muzan pinned you on the bed and started marking you up.