touching

Hello Rabbi Michi
After issues I read in the Gemara and after reading various articles by Rambam, etc.
What kind of touching is actually forbidden?
There is casual touching, there is close affection, and there is consensual (sexual) affection.
Is a brief casual touch of a hug between friends or relatives (aunt, cousin, etc.) forbidden? Because in such touches there is no affection, but rather a closeness that does not lead to any forbidden appeals.
And the Rambam writes that the one who hugs and kisses is through lust (sexual affection)
So is kinship love also forbidden or only kinship (sexual) love?