I loved your "naked under duvet" thing... well what about getting the duvet again on the couch but with a twist.. just go under the duvet dressed as you are then try to strip naked under the duvet without being noticed.. you will then be again trapped naked under the duvet again..keep masturbating then till you are "free"...
and what about an elevator dare? go to the last floor with the elevator, then start moving down floor by floor, each floor take off an item of clothing and throw it out of the elevator...go on till you reach the bottom floor, if naked before the bottom floor edge instead of taking off one item, then walk back to retrive your clothes, do not redress..cum naked in front of your apartment door before you enter
Have fun