Kissing

Two grapefruits were in love, so they decided to kiss each other.

The problem was that they tended to roll away from each other, due to each other's bitterness. But they truly loved each other, despite the fact that they were grapefruits.

Finally they realized that the only way to kiss each other was if one of them cornered the other in a spot where it couldn't roll away. The idea was a stroke of genius, and they have been kissing each other ever since.