[Good question. Crystal's not shy on giving her team a little spoiling when they deserve it - and Chumee's almost always hugging onto her in some way, when she's not being used - so she doesn't exactly have any experience...]

It's probably best to give them some, just to be sure. I'm not completely sure of this myself, but I think it at least counts for you, so if you're too shy to just... go out and touch someone or something like that, you could probably keep from getting sick by cuddling with your pokémon for a while.

[Like she did while she'd been avoiding her main touch-givers. Or one of them. The one who insists on hanging off of his friends.]

I'm not really about to test out if pokémon can get sick by going without a few touches though. It seems a little mean.