They want butterflies, dragons and Celtic knotwork, especially one that looks like a thorned heart.
I have them lay down on a mat so they'll be still and so gravity will assist draping henna lines fast and smooth. I do simple patterns large, with thick lines so there'll be plenty of henna to stain. I kneel over them, like a henna predator, to line up the pattern straight with a backbone or around a navel. I sketch it in first with a Stabilo pencil, after a quick wipe with rubbing alcahol to clear off any sunblock or lotion. After the fast sketch, I grab the carrot bag and speed-sling.
They lay out on the mats, listening to the rock bands, and let the henna dry. I tell them they can get up when they're "crusty and cracked" and they giggle. Guyz wander by and stare at the array of bottoms with pants pulled down to butt cleavage.
Hours later, the gurlz come back and show us the brilliant orange stains, already darkening from heat and sweat. They've taken pains to keep their henna nice in this crowd!