Is there such a thing as platonic cuddling?
Sleepless in Seattle
The obvious answer is of course, yes, such a thing occurs. It is possible for two people to be affectionate towards each other with the absence of sexual intention. But I get the feeling your question is more whether or not it is possible for it to remain completely chaste. And that's where things become, as I'm sure you know, a bit more complicated.
I try to think of it in very basic terms: There are some things that you do with friends and then there are some things you do with your boyfriend and / or girlfriend. And while some of these things may overlap, "gently touching each other while laying down" tends to fall into the second category. Any time there is intimate physical interaction, it's bound to bring up certain connotations that come with being in a relationship, no matter how casual it might be. Even when your intentions are purely innocent, you still run the very high risk of someone getting the wrong idea or having their feelings hurt in the end.
Also, I feel it might be best to avoid things that help to develop the part of your persona that can detach emotionally from an intimate situation. You should save this kind of interaction to share with someone that you truly care about as more than just a friend.
Betty Johnson - "Cuddle Me"
Okay - "Pretend"
Tender Forever - "This Is Hardcore"
Lucky Dragons - "Mirror Friends"
Tenniscoats - "Oetsu To Kanki No Nanoriuta"
Palms - "End Of Term"
New Order - "Regret"
Cardigans, The - "Heartbreaker"
Cornelius - "Chapter 8: Seashore & Horizon"
Arthur Russell - "Soon-To-Be Innocent Fun / Let's See"
Film: When Harry Met Sally...