I don't see why you just can't give him a few (5?) minutes cuddle when he needs it. You said it yourself, he is sensitive. I don't even know why you can't snuggle for a few minutes when his friends are over. I don't think they will mind. If you have to stay outside, just sit down on the grass or curb or something and snuggle with him there.
And as far as your daughter is concerned, please give up ideas of things being EQUAL. In addition to it being impossible to achieve absolute equality, this notion can be harmful. First of all, it presupposes that your children will need equal things, which they won't; and secondly, it will give them the false idea that everything in life should be fair and equal. And life's not like that.
If you give your son more attention than you give your daughter, that is FINE.
It's quite likely your daughter will be less sensitive than your son, and won't REQUIRE the same amount of attention. Therefore, why give them the same amount?
Nothing in your children's lives will be equal. One will be smarter. One will be better looking. One will be better at sports. One will make more money. Etc.
Give up notions of equality, and give your son what he needs.
p.s. I had a vivid dream last night that my oldest son was 5 again (he's 22), and he was sitting in my lap and we were reading and cuddling. I could even hear his sweet little voice the way it used to be. It was delicious. It makes me tear up even now thinking about it, my dream was so vivid. So cuddle with your little boy, and soak in every second.