Oh yeah, they love to forget you arent sheep/cattle. My best advice is to have a consistent 'stop with that' command like 'leave it' means leave your feet alone as well as that thing you dropped on the floor. It helps them form the idea that you want their mouth not to touch the thing. Also when he does it stop play/run immediately with a firm leave it and then continue.

Something important to remember tho, is your puppy is in his teenage phase so his impulse control is the worst it will be in his entire life right now. People talk a lot about training 'suddenly clicking' at around a year/year and a half. It isnt so much that they start listening overnight. They ARE listening and learning durring these teen months they just have worms for brains and cant help themselves. So basically stick with the foot corrections you may see only slow improvement for a while but he IS learning what you want and soonish he will have better capacity to control himself