In college we had the "war room" for just this purpose. Any and all risks for intel leaks were accurately predicted and eliminated by a crack team of secret operatives.
We had a complete language of code words to use in risky public situtions. Every girl was given a code name. Phone numbers were always encoded, in case they were found by another girl. We even used fake names (and even accents) ourselves, to prevent info from getting around. Had a pretty good sytem going for about 2 years.
Me and one of my friends tied for the single semester record with 13 actual relationships (defined as more than two dates/meetings, and some sort of nakedness)