Open pipette and have it reafy to grab, play nice stroking the head and neck, wiat till they seem relaxed when you have aprted the fur keep stroking, grab flea stuff and squirt fast, with it as close to neck as possible.
If some goes on the dur just leave it.
Go back and rest while they run away, and then they will come back wanting to love you.
Its the alcohol in it that they hate cos it is cold when it lands on them, if it was warm they proberly wouldnt notice.