Ik this is one of the oldest scenarios on the book BUT Ima shill for this in Passthrough. You walk in on your incredibly flexible and hot roomate who totally is not Katie Kush 😉 doing yoga/stretches until she decides to show you some "new streching positions". What she actually means is she wants to do the splits on your cock. Would need an actress that has an awesome ass and is incredibly flexible
Positions to include/consider:
Doggy with legs spread/stretched out wide
Reverse Cowgirl while doing the splits
Missionary with legs tucked behind head or alternativly just stretched out as wide as possible.