Urban legend. I know someone that wrote for Spin for many years, interviewed Vedder multiple times and confirmed that’s not the origin of the name - the peyote mixture is. But even without that, does it really make sense a grunge band, who were pretty badass at the time, would name themselves ‘cum’? 

 It's fun to lose and to pretend 

 Needing to adapt to the wrong
A cause of much venom