Is it permissible for a mature, sane girl to sit on her maternal uncle's lap and embrace him out of love?

It is not permissible for a mature girl to sit on her maternal uncle's lap, even if it is not with desire, because the most that is permissible for the maternal uncle is to touch the places he is allowed to see. There is a disagreement among scholars regarding the extent to which it is permissible to touch everything that is lawful to see, because touching is more intense than seeing.