I sometimes sing all three parts at once. That is,

Snap say it's Crackle that Pop's the sound
You gotta Snap have Crackle when Pop's around
You can slap tickle hoppin'
When the clap buckle poppin'
Snap! Crackle! Pop! Rice Krispies

Of course, people do tend to wander away before I'm finished....

Aloha,
Mark