Edit: Sorry, I don't want to come off like a dickhead if someone doesn't speak English naturally.
A bass guitar is still a guitar. A guitar is just a stringed instrument. I just didn't feel the need to specify bass really.
Abs like that, you need to have some skin tone (cant see it on super pasty dudes like myself), then you need a low fat percentage, some oil, then dont drink water for a while so youre dehydrated AND do some situps before you go out in the world to get your body a little pumped.
You do that and do about 100-300 situps a day and youre good.