Madhi

Asalamu alaykum,

How does one wash oneself of madhi? Is it necessary to rub or is pouring water over where the madhi is sufficient? I notice that it sometimes depends on the situation as sometimes its thin and water washes it without rubbing.

I will be honest and say I found it difficult to accept that madhi is najasa as it constantly comes out with or without thoughts involving sex. However, the narrations say it must be washed and wudu needs to be performed. I thought to myself with regards to the narrations about madhi and Ali's (as) having excessive madhi that Muawiyah or some enemy of Ali may have wished to humiliate Ali and say it is najasa to make him look bad so this enemy of Ali may have fabricated or modified a narration to make Ali look bad, weak and ignorant but ALLAH MOST HIGH knows best.

jazakum ALLAHu khayr