Probably one of the neatest-looking filmic examples of this appears in Crouching Tiger, Hidden Dragon (2000). When Jen pursues Lo to get back her comb, their fight gradually becomes a lovemaking session. Probably the strangest part of the whole affair was when Jen spontaneously stabs Lo with a knife (which breaks in his shoulder) and then half a second later, they're kissing passionately with his blood dripping down their chests. A memorable image, to be sure.