Last time, I tried to put the apple juice/milk/water (something he liked to drink) into the 針筒 (not mixed with the medicine) just to let him know that those juice from the 針筒 tasted good (in fact, I tried his medicine that's really sweet).
Soon, he accepted to drink those sweet medicine from the 針筒. Now my bbs are running to me when they see me holding the medicine bottle.
But of course, remember to keep your smiling face when feeding BB and feed slowly not to choke him la :-P.