In the American southwest and Mexico, there is no lisp in the speech of the general Spanish-speahing populace. 'S' is O. K. I was taught some Spanish by a Colombian university graduate (doctorate) and he said that the Castilian lisp was considered effiminate.

However, the 'S' is short, not drawn out with a shhhh or whistle in the manner of many Americans (Try yourself on Adios- I often end up with Adiosssh- which immediately identifies me as a gringo).