Maybe you just need to try harder. Don't expect a rabbit to come to you and ask if you could please feed me by syringe, you have to catch him and hold him tight and just do it. If you can't maybe ask your parents can help with that. You keep asking questions online maybe just put your phone away and interact with your rabbit instead, having both your hands available, hold him, pet him, massage his belly, train him to tolerate that you need to hold him, we can't do it for you here unfortunately. It's you have to do it yourself, try, try again, try harder. Here's 6 pages on this thread and you've got lots of advice what to do, how to do it, there's nothing new we can suggest, now just do it. Sorry I don't mean to sound rude, I fully understand you want some assistance, ask maybe your parents can help you hold him.