Male dog being constantly humped by others

Hi everyone,

I really need your advice. My puppy, who is 6 months old now, is constantly being humped by other dogs. He's a little male, but it happens every time. I don't think it's a dominance thing because it's honestly crazy; dogs seem to smell him from a distance and just bolt towards him. We can't go to the park anymore because it's a total nightmare. Four or five dogs at a time try to mount him and they're absolutely obsessed – even their owners can't get through to them.

During the week, a little female dog spends the day with him, so I was wondering if she might be transferring her "girl hormones" onto him. What do you lot think??

Thanks for your help, I'm really at my wits' end.