Shot-clog \Shot"-clog`\, n.
     A person tolerated only because he pays the shot, or reckoning, for
     the rest of the company, otherwise a mere clog on them. [Old Slang]

   Here's some more info …

     a bore tolerated only because he or she pays the [1]shot

     Examples:

     I'd planned to reimburse Jerry for the meal via PayPal, but after
     sitting through a lengthy evening of him holding forth on myriad
     topics, I decided it would be an unfair challenge to his reputation
     as a shot-clog.

     "Alas! I behold thee with pity, not with anger: thou common
     shot-clog, [2]gull of all companies; methinks I see thee walking in
     Moorfields without a cloak, with half a hat … borrowing and begging
     threepence." - John Marston, Ben Jonson, and George Chapman,
     Eastward Ho!, 1605

     Did you know?

     The [3]shot in shot-clog refers to a charge to be paid. It's a
     cousin to, and synonymous with, [4]scot, a word likely only familiar
     to modern speakers in the term [5]scot-free, meaning "completely
     free from obligation, harm, or penalty." The origin of the [6]clog
     part of shot-clog is less clear. Perhaps it's meant to draw a
     parallel between a substance that impedes a pipe's flow and a person
     who impedes a good time; or perhaps companions' tabs accumulate
     before the shot-clog as so much [7]dross in a clogged pipe, while
     the shot-clog yammers on unawares. The 17th-century playwright
     [8]Ben Jonson was particularly fond of shot-clog, and while the word
     is no longer in regular use, it might work for you as a suitable
     old-time insult for that person in your party who is fine to have
     around so long as they pick up the tab.

   [9]Word of the Day: Shot-clog | Merriam-Webster
     __________________________________________________________________

   My original entry is here: [10]TIL: shot-clog. It posted Sat, 01 Jun
   2019 00:28:57 +0900.
   Filed under: education,

References

   1. https://www.merriam-webster.com/dictionary/shot
   2. https://www.merriam-webster.com/dictionary/gull#h3
   3. https://www.merriam-webster.com/dictionary/shot
   4. https://www.merriam-webster.com/dictionary/scot
   5. https://www.merriam-webster.com/dictionary/scot-free
   6. https://www.merriam-webster.com/dictionary/clog
   7. https://www.merriam-webster.com/dictionary/dross
   8. https://www.merriam-webster.com/dictionary/Jonson
   9. https://www.merriam-webster.com/word-of-the-day/shot-clog-2019-05-31
  10. https://www.prjorgensen.com/?p=2968