Who's mastered this one? Me and the OH have tried various stuff and it's really hit and miss.
Chocolate sauce is still our favourite, and good seeing as you can just buy it innocently from Tesco! (Although the time when I bought a cucumber and chocolate sauce together on their own was awkward, was definitley a discreet "self service checkout QUICK!" jobby!)
Weirdest we've ever tried was golden syrup. We were extremely horny and it was... interesting! A bugger to clean up after too!