George Wishart and fox hunting

I’m puzzling over the alleged words of the Scottish reformer, George Wishart:

‘…a priest standing at the altar saying Mass, was like a fox wagging his tail in July.’

I don’t have a clue what foxes do in July. I gather that foxes wag their tails when they’re happy, but from Wishart’s following words, it is something about being false.

This is the charge in the second article against him at his trial:

‘Thou false Heretic did say, that a priest standing at the altar saying Mass, was like a fox wagging his tail in July.’

The Answer:

‘My Lords, I said not so. These were my sayings: the moving of the body outward, without the inward moving of the heart, is not else but the playing of an ape, and not the true serving of God; for God is a secret searcher of men’s hearts: Therefore, who will truly adore and honor God, he must in spirit and verity honor him.’

Then the Accuser stopped his mouth with an other Article.