Does impurity transfer to clothes or the body when sitting on or touching impure clothes, given that the body is moist and there is no color, smell, or visible trace of the impurity?

If a person touches dry impurity, it does not transfer to him, nor do his clothes or body become impure thereby. Impurity only transfers with the presence of moisture.

If the impurity is very slight, to the extent that it cannot be seen with the naked eye, then it is excused, and the garment or water into which it falls is not judged impure, due to the difficulty of avoidance and the hardship involved.

The advice is not to succumb to these whisperings, for the religion of Allah is ease.