I have had to put drops in ears before and its a nightmare. I think the best thing is to put the drops in and if you have a floppy eared bunny (mine always have been) to hold the hear up and massage the base of the ear (you should hear the drops squiging around).
I have found, and the vet also told me, that the drops will drip out a bit, the rabbits I have given drops to have always looked such a mess as the drops are greasy and get into their fur. The bunnies don't seem to be able to wash it out very successfully.