To 'Blow Your Beans' or 'Blowing Your Beans' refers to the act of achieving orgasm or 'cumming'. Generally it is a term used for the male orgasm. However women have been known to use the term too.
Billy - I was goosing my bird last night and she wouldn't let me finish inside her. So I pulled out and she said you can BLOW YOUR BEANS all over my tits.
It means close to something like a kidding around or to joke around.
It can be said as "bustin beans" also.
after saying you were bustin beans you should say "forget about it" but it is said with an Italian voice....like Mario
friend 1: i ate your mom out last night
friend 2: what the fuck i will kick your ass
friend 1: dude i'm busting beans here! forget about it