lol, well it looks like the problem's all in your head, but if you're really worried about it, I've always found cable curls where you really squeeze at the top seem to take the forearm out. You could really be sneaky and try them with your wrist cocked back, too.
Another curl I've found to be all biceps is the prone incline curl. You lie face down on a bench set to an incline, let your arms hang straight down and curl them up. What I've found to help is to think less about curling your hands up, but flexing your biceps instead. Gets a good ole squeeze.
All about that MMC, broseph