Angle the needle toward the insect's head and keep the tip close to the cuticle. Allow solution to circulate for 30 seconds-1 minute. Cut off insect's head and legs, then cut off last two segments with scissors or forceps. Squeeze out guts into the petri dish and squirt lightly with plain saline. Tease out the tubules and view under high power on a dissecting microscope.
Female crickets are usually full of eggs that look like yellow rice.
Male crickets tend to be smaller and are easier to assess. Dispose of CPR and other chemical inhibitors as directed by your institution's safety office. Plain saline can go down the sink. This is a subjective measurement and therefore is a little tricky. You may want to decide in advance which sample you predict will show the most uptake and arbitrarily assign that sample a maximal value.