They commented on how they almost ruined the scene after the filming. Desi couldn't control himself and Lucille had to bite the inside of the cheeks. The cast of I Love Lucy had always tried to spring surprises to keep reactions real.
"I Love Lucy" episodes "Ricky Has his Eyes Examined and Lucy gets in the way as always, so than she gets her eyes dialited and can't see to do her dancing number at the club! Which when she perform with her partner is hilarious!