I can still taste his horrible cum in the back of my throat, hours later...

How can I get rid of this? Clearly I'm never seeing him again. Idc that he's a gentleman or that he's physically perfect. Worst tasting cum of my life. It was so sour and nasty. Tasted like bad milk or something.

EDIT: I've brushed my teeth, gargled, eaten and had plenty of water, it disappears while I'm eating or drinking then all of sudden comes back when I'm done :(