The "flip side" is the reverse side of a vinyl record, a term often used by radio DJs. They might say "I'll catch you on the flip side" to mean they will let a particular album play through, and won't start talking again until they have to change or flip records.
"flip flop" is a variant used originally by truckers to mean a U-turn or the return trip, and may be used instead of "flip side."
1. Boondock Saints-"Catch you on the flip side" before he goes into the restaurant and kills 3 guys in it.
2. Tarzan, if i dont make it to the temple of kuakuamakimuno i'll catch u on the flip side. btw watch out for that tree