You just need to drill a hole and tap it (thread it) and then get a fitting at Home depot. thread to tube fitting. I want to say most are 3/4" but i am not postive. Have to look at mine. I also think i have a tap if you need to barrow it. I know i have a tap but can't remember what i used it for, so it may not be the right size.
I would gowitha 3/8 hose and 1/2" NTT hole on the cup then get a 1/2 rpt to 3/8 hose barbed fitting made of nylon. Still going to have to take out the cop to clean it.