Help with a procedure

So I have been modding quite some time now and only now decided to make an account to request help, I have gotten the procedure working sort of ok:ish and I really need some help on it. I am making a "item" that shoots out firecharges everytime i right click and the thing is I have gotten it to shoot out firecharges with the rightclick but I cant remember how to get it to shoot the firecharges in the direction I am looking at, help would be appreciated, Thank You!