Is it permissible to wipe a child’s private parts with the right hand when changing a diaper if one is not skilled at wiping with the left hand?

The general rule for Istinja' (cleaning oneself after relieving oneself) and for cleaning others is to use the left hand, because it is designated for impurities, and because there is a prohibition against performing Istinja' with the right hand. This is out of reverence for the right hand and to preserve its honor. It is recommended to use the right hand for all matters of honor and veneration, and the left hand for matters contrary to that. So, whoever cleans a child, it is recommended to do so with their left hand, in accordance with the Sunnah. It is disliked to use the right hand when one is able to use the left, unless due to incapacitation or illness.