It's true -- the whole height-dominance thing is rather disputed now. Of course, letting an aggressive bird perch by your face isn't a great idea because of the potential for getting bitten there, but they don't become aggressive BECAUSE they're on your shoulder.
BUT ANYWAY....you have a fiesty little lovebird pet. They're small, but they can be little brats if you let them, and it seems as though you have. What do they do with each other when one is being a little too bratty? They reprimand them. Yelling isn't going to work. You have to do like they do -- bicker back. When you have your lovebird out, and he starts going too far, say "Noooo!" with a raised finger to catch his attention. If it continues, repeat, and gently but firmly tap him on his beak. If it still continues and your reprimanding doesn't seem to work, then return him to his cage. He thinks it's OK to keep doing what he's been doing because he hasn't been "told" in a way he understands that his "preening" has gone too far.
Watch the video below. I know it's macaws, but it's the same basic idea. Notice how the scarlet lets the catalina know when it's "going too far" -- raised foot as a warning, with a lunge as the next step. When you raise a finger in front of your lovebird when he first "goes too far" and say "Noooo", you're giving basically the same warning, and one that your lovebird can easily understand. By pairing the "Noooo" with the finger, you're introducing a verbal reprimand which will later (if you remain consistent with pairing the finger with "Noooo") work on its own. If he goes further, the tap on his beak with your finger means the same as the lunge you saw the scarlet macaw do. It's basic universal parrot-speak for "Hey! Enough already!"
Another little clip, very short, but you can see that these two linnies are bonded, but still bicker when one "goes too far".
And finally, one more, a little longer, showing hyacinth macaws. Pay attention to how they let each other know they've "gone too far" yet clearly they don't "hate" each other -- they bicker.
Speak your parrot's language and you'll more easily be understood. I have a 22yo
amazon and we've come to various "understandings" about things over the years together, but that happened only because I tried to make things clear in the ways he'd understand.
