While it's true that cork "breathes" after a fashion, you may be better served by just letting it age, sometimes with the top on, sometimes off, shaking periodically. There are faster methods of steeping, but I'm not sure cork would "breathe" well enough for your purposes, and I'm not sure it's really necessary....
Sigh. This post got me drooling over fine French wines, LOL. Not sure why, but it's giving me the giggles
Anna