Hey Obi1,
I'm back. I was away for a little bit with the RCU crash and all.
I'm not a super radio guru. I have only experience with the basic JR systems. If I were you I would post a question on the radios forum (under airplanes on the RCU main page). Give your exact radio make and model and let the experts know exactly what you want to do.
People use flaps for lots of things. I haven't experimented a lot myself, but in aerobatics they are using them for super tight loops and that sort of thing.
I talked online to a guy named Craig with an Ultra Stick 60 once. He said he put his flaps on a three position switch to go up centered and down. He said that he used to roll inverted, put the flaps up and fly that way about 5 feet above the ground in circles. He said it was a hoot

, but he almost put it in several times doing that

.
On my Basic JR, my flaps are controlled with a two position switch. I noticed that the switch is easy to bump by accident when I hand release my Sudokhoi to go straight up. It was kind of scary for a few seconds because I wasn't expecting it.