Red Man has a VERY ticklish right nostril. If you tickle the little bottom part, he'll 'smile' for you xD Cracks me up every time, poor guy.
Loki always seems to have a very relaxed mouth. Whenever I groom him I can't help but to mess with his floppy lips. I was detangling a large knot in his mane once and he pressed his front teeth against my shoulder and just messed with my shirt with his lips. I started laughing, as probably not good as a behavior as it was.
Sam will lick your hand and if you rub his belly when he's relaxed he'll 'drop anchor'. Not good when your grooming and theres kids about