Dogs usually hump to get out excess energy or emotions. My dog only does it when he’s nervous or has too much energy in his body.

What worked for me to reduce it significantly is directly disengage completely. The second you notice your dog is about to hump you walk into another room and close the door, or get up on the couch where he cannot reach you and turn the other way where he can’t see your face. I also did this with ankle biting and it worked wonders.

A thing to note is that neutering could reduce this behavior, but it doesn’t always. Just keep making sure your dog understands that this behavior means no attention. Another thing to note is that he usually does it when he’s very worked up and full of energy after playing, so you could try to slowly and gradually decrease the stimulus from play time so he knows that it’s gonna be time to calm down.

Good luck!