Similar to the beer belly, the SitnSip is a novelty product designed to hold your beer at ball games, voting booths, or your bedroom. The difference is that instead of hiding this in your gut, you sit on it, which may be hard in stadiums where they ban outside beer. Should still be OK for little league though.
Luckily for you, the SitnSip is insulated from both heat, cold, and your stinky rear end. It holds 8 beers, and you can grab one for $24.99.
Product Page [SitnSip]