Take a paperclip, bend it out into a straight bar. While gently holding the fish in your right hand, with your left hand, push that round bar into the mouth and push the lower jaw down (if I is a fish viewed from above, then a T is the fish with the bar across it's mouth, holding the lower jaw down). Then drag the fish backwards, up and out of the water. Shouldn't have to do it more than 2-3 times and the eggs/larvae will be flushed out. That's how we did it for everything from Frontosa to Tropheus. It may sound "traumatic" and I'm sure it is, but I'm also sure it's quicker and less traumatic than annoying the fish to the point where it spits on its own!
FWIW,
Matt