You might not be wearing shirts that are meant to show skin--they just happen to "ride up" when you bend down--but how he and his friends view seeing your skin may be different than how you and other adults view it. However, you don't have to change everything your son doesn't like or feels uncomfortable about, either; I think it's good to try to accommodate them to a point, but not to the point of the child being the one who tells Mom what to do.

But, in this case, you could use it as an excuse to buy some new clothes!