What do you do when the boy is ready to ejaculate when you give him hand?

Hi I really like this boy and we are 14 and I think I am ready to give him hand. Some of my friends have told me that when he is ready to ejacualte, you are supposed to bend the penis towards the stomach so that the *** doesnt spew all over the room. But, if the penis is erect, how doe it bend? Please help me!! I want to do it with him tonight!