Mine do it too, and they're 8 years old now.
What is slightly weirder is the recent habit that Zelda (the male of the two) has recently picked up, which is to snuggle up and sniff my armpits once an evening before coming back up for air with a very contented look on his face, and a slightly puffy tail. It's a little bit... Well, a little bit pervy if I'm honest, but it keeps him happy enough.