Ok, I just noticed something kinda hot...I just found a scene where Jack is TOTALLY, brazenly taking a peek of Ennis's goods. We know Jack restrains himself while Ennis washes himself with a washrag, but look at the "My daddy was a fine roper..' scene.
Right after Ennis says: "...he thought all rodeo cowboys was f***ups', look at Jack's eyes.
Now, remember, Ennis is sitting spread legged and holding his cup up high by his chest. As Jack says "The hell they are.' his eyes dart DOWN. Taking a peek at Ennis! hmmm? Not at Ennis's cup. Jacks eyes then go back up to Ennis face. But get this. Right BEFORE Jack does the YEEEE HAW!!, look at Jack's eyes AGAIN give Ennis the once over!
Don't tell me Jack is not horny!! Check this out!!