Among some teens on the Gulf Coast, there was a protocol regarding who could initiate a kiss. The rule was that starting a passionate kiss underwater was a female perogative, and it could last as long as both stayed underwater. This gave the couple a modicum of privacy -- others could figure that they were kissing; but how deeply and whatever additional affection could take place was not visible to others' eyes. Teens in a group sometimes find it hard to obtain a little privacy. You develop over time an ability to hold your breath longer, especially there's some heavy petting that may require any adjustments! Also, it's nice to take the lead sometimes.