Stop and Go
First, get into a brain twister mount:
Throw a strong sleeper. Point the index finger of your non-throw hand out and bring the yo-yo up. Now move your throw hand under the yo-yo and up again on the other side.
*For more detailed instructions, go ahead and surf the web*
The trick itself
Okay, now that you are in the brain twister mount, bring your throw hand up and under your non-throw hand so it forms a sort of cup. Now move your hands up a bit and the yo-yo will come up to your hand. Be prepared to catch it. This is the "stop" part of the trick "stop and go".
Now for the "go" part. Bring your throw hand under the yoyo and twist it so your fingers point away from you. Now pull your throw hand down and leave your non-throw hand where it is. The yo-yo should start spinning again and you are ready for more tricks.