Two bits of String go into a Bar One is straight & tidy The other is all screwed up & tatty Barman turns to the tidy bit & says " we don't serve bits of String mate " Looks at the tatty bit & says , " I just told your friend we don't serve String & you're String aren't you " He said " no , I'm a frayed Knot !!".
Nope! that's grammatically incorrect. If you wish to use the past tense of "drink", you would then need to use the past tense of"pistol" (there isn't one) the joke rests on the double-entendre of vocalising it and one would not, in the day, carry a" pisdtol" no matter how rustic the dialect.