possibility 1: this is a more standard manga and she just went to the wrong room while drunk and MC is still a virgin
possibility 2: she planned it all like an evil boss for the purpose of getting an OP otherworlder as her servant
exact details may vary, but that's pretty much it for likely paths for the series to take
I mean, I suppose it *could* go the ecchi route and he did get some and will get more soon, BUT that usually doesn't happen when MC is too drunk to remember