K.T.
I know what you are going through. My daughter is 25 months. She will tell me she has to go potty however she has already gone by the time we get there, but she will throw a fit if I don't let her sit on the potty. She asks to go to the potty about 100 times a day. I can understand your frustration as I am frustrated myself. At least your son will take his pants off before her goes. Mine just runs to the potty and apparently goes while running. I know this isn't any advice that I am offering, I just wanted you to know that you are totally not alone. I am in potty training dilema with you.
K. T.