وعليكم السلام
If I have understood the question correctly then it has been answered previously:
http://www.noorulislambolton.com/latest_answers.asp?qa=4224
Please also listen to Moulana Muhammad Kalim’s Weekly Fiqh Class on the etiquette of visiting the toilet:
http://www.noorulislambolton.com/audio/1106.mp3
And Allah knows best