Out of my five, the only one who humps is my girl Darry. When Radar first met her, he 'jumped her bones' as soon as he saw her, but after she got over the initial shock, it's been all her.They're a bonded pair, and she's constantly on his back.
Both my boys are VERY polite like that. I've never seen Dill hump, either, not even when he was bonding with Sherry. (They're blessed with a more equal partnership than Darry and poor, besotted Radar).
Pipp is very dominant (she and I are a bonded pair), but she just 'digs' me. :biggrin
and the gang of five