I'm with Marke's suggestion that you share some of your dinner with your boy...hand feed him. Not many dogs will turn down roast chicken or sirloin steak. Let him breath in the aroma...get his mind into his stomach and not his "man-bits."
BUT, here is a question: Is he engorged? Is he swollen up, which would definitely indicate a female in heat? If he is, then, your Romeo just needs a Juliet or someone (we are all adults here), either the vet or you, to lend him a hand.
I'm going to get mail on this one, but it is common with farm animals.