I'm okay with tips in the side of my belt or back of my bra strap. If people want to tip me "near the goods or girlies" I won't accept it. It's mostly women who tip me anyway, most men seem too shy! I've also carried around a basket on my head in a resturant venue, not as many tips as the costume collecting. I've also had a venue with a tip jar for the dacer at the register. That didn't work very well at all! People really want to feel involved with the dancer. If you are in a nice venue, are confident, and can gracefully handle when things go wrong, I don't see a problem with costume tipping when done respectfully by patrons. When I go see other dancers, I give them the bill shower because I like the tradition and it lets them know I might be another dancer to chat with after the show if they have time.
I play a game with my students where we arrange chairs around the room, and have one student be the "dancer". The other students are customers with different personalities, i.e. obnoxious drunk, overly excited dancer wanna-be, small children, hostile woman, pervert tipper, etc. Other students are wait staff who generaly try to get in the "dancers" way
The students have to handle the customers, keep their bottoms out of the diners faces, collect tips (we use kleenexes for class) appropriatly, not crash into the staff, keep track of their props, and use the floor space well while dancing. Sometimes I even put in the wrong music...Hey it happens!