Litten enjoys being pet under the chin, on its stomach, on its whiskers, and on its head, in that order. It dislikes being pet on its paws and ears, in that order.
IT ALSO ENJOYS HIGH FIVES .

You can hold the touchscreen on both sides and it reads it as the middle of the screen so you can pet it without touching it.

You can also slap your pokemon but I haven't figured out what specifically causes that.