When receiving a handjob, the act of stroking the penis slowly and gently then stroking it quickly with great speed causing a vibrating effect, that ends with the head extending over the foreskin and finally ejaculating all over the hand. Very similar to letting a dog outside then scratching its belly quickly and it's mouth slobbering all over your hand. This is not limited to a having partner spot you, as you can in fact do this by yourself in the act of masturbation. However, this sexual act cannot be performed on a circumsized penis.
1. Hector asked Monica if she could give him a blowjob but instead he had to settle for less when Monica chose to let the dog out on Hector instead. 2. Stefan could not get a girl to let the dog out on him so he chose to do it himself.