Jacking off is when you take your hand, and grab your cock like there is no freaking tomorrow, make sure you have a firm grip! Move your hand up and down and up and down again and again, if you do it right and long enough, you'll ejaculate all over. Sometimes you want to eat some, so you do. I do it like 3 times a day, and sometimes I'm dry by night, but I love it so much, too bad I can't reach down to give myself a blowjob!
I was jacking off in the bathroom at school and it went "thump, thump, thump" until it just all came out and I was relieved that I let go of my seed.