Figured I'd put in my two cents on this. It's a shame that your frog is having this issue right now. One of mine is doing the same thing but I think just because it's winter he's trying to hibernate. But he's stying nice and chunky so for now he will be fine. For me the best method that I have used involves 2 people. the first person just gently puts their hand behind the frog so it will not jump away and with the other hand gently rub the frogs lips. For me it usually only takes maybe 2 or 3 touches and the frog opens his mouth and have the second person gently put a piece (whatever you might be feeding) in and the frog usually eats the rest. no instruments needed and of course gloves are to be worn.