I have an 11 month old nephew and he's really well behaved, happy, playful etc. However, I think I've got him into a bad habit. From 6m+ I'd let him play with my face whilst holding him; pulling my nose, slapping my cheeks and I'd make funny noises etc. It made him laugh and still does, but he's getting bigger and stronger now but won't stop. How can I put a stop to this? I'm not worried about my face but in case he thinks it's normal.