Honestly I think they're both quite nervous - especially Kai. Touching each other may be their way of calming down, since they know each other so well. Exo is a very touchy-touchy group after all. KaiBeak is such a cute friendship.
Exo has said Kai is a shy person. I'm quite positve that these guys didn't have a choice about being in this group. It defianty helps shy little Kai, that his hyung who he is comfortabe with, is around. Touching him calms his nerves, its so cute.
*definitely you mean... also we don't know whether they had a choice or not. All I know is is that they looked like they enjoyed being in SuperM and gave it their all and asked fans for support but instead fans decided as usual that they knew better and continues shun the group. It's absurd.