I vow to abstain from misconduct done in lust.
Though sex is the strongest of all desires, this precept can truly extend to all desires based in lust, as the Kwan Um School of Zen teaches. My own Hanmaum precepts simply added, I vow to keep a pure mind.
I couldn't decide which video to choose, but I think they both do a good job of showing what can happen when of seeds of Karma are sewn out of lust. The fruit that grows tends to be bitter.