No I would never recommend blowing anything down a cat's mouth for fear of choking them
Here are some tips for peeps
http://icatcare.org/advice/how-give-your-cat-tabletIf you have problems, do you have a neighbour who might help?
I too am baffled as to why your vet will not let you have flea and worming treatments before giving the flu jab as they should be given more often than annually
and I would very much prefer NOT to give all three at the same time unless the cat is very difficult to handle.
Obviously vet has to be sure of cats weight with certain treatments but if cat goes to vet for regular check ups, the weight should be on record. Some worming pills are much easier to hide than others but you need to cover roundworms
and tapeworms. Drontal are usually much larger than Milbemax so we prefer Milbemax