He is showing classic signs of becoming aggressive especially rubbing his head on you.
Yep. We only let one male lamb keep his b*****ks this year (the rest all had faults, but this one is very nearly perfect). In hindsight, that was a mistake. We don't have another tup, so he's been "the one and only" since the day he was born. He also gave me a bit of a butt this week, and tried the head rubbing thing too.
I immediately caught him and tipped him, then sat on him for a minute in an attempt to teach him that he's below me in the pecking order. He then ran off tail between his legs, so I'm *hoping* that's a lesson learned.
He's still small, so this isn't a big issue - yet. However, if he tries it again, he'll be going for meat no matter how good he turns out, as I won't have him in our flock, and definitely won't sell him on. I do wonder if a lot of this is because he's never had to establish himself in a pecking order with other males?