Bros - pop in some songs like
Metallica - I dissapear or On the Road again (turn the page)
Savatage - Edge of Thorns
Jimmy Hendrix (the harder kind)
Sepultura (roots)
Start flexing, and try to "beat" the musics tempo. Youll know what im talking about once you try it. Flex it like theres no tomorrow. I do this every night before bed, I break a fucking sweat - keeps my muscles in shape especially if I couldnt work em out because of personal life etc. You can make them sore and work em like this. Even if youre advanced. Youll eventually discover new angles of flexion every week and this is a kickass feeling - you hit never before hit angles (not seen in the muscle, but you can feel it) and you can actually make yourself grow like this. Of course, use only as a substitute for training.
I use this as a 2x per week training. I train the bodypart once with weights, and second time, when its healed, i FLEX it. But my definition of flexing is apparantly different than yours. Bros, flex like a motherfucker. It gives you the biggest test surge i fukin swear. You could do this in the morning to so you start your day as an aggresive motherfuck.
Enough rambling - those are my views.
BTW, to answer the question (whoops) my left bi is .5 inch smaller. it appears to be much smaller though because my left rear delt is smaller as well ;