Need tips on how to do wam sessions at uni. Ensuite room in shared flat in halls but shared kitchen.

Take it to the hotel/
Motel/
Holiday Inn...

Or outside, preferably near a river/stream/creek

I second n1rul1m's suggestion: a motel/hotel (or anywhere similar that you can get some privacy) is your best bet.

Get a hotel. If you're really going all out, try to find a modern hotel and get an accessible room. Usually the shower is bigger and has an extra hand held spray, making it easier to clean up. Don't forget the "Do not disturb" sign.

Don't try it in your dorm room and risk getting caught by your roommate...(and don't ask why I know this is a bad idea)...