Short for Tim Horton's, also known as "Timmy's" or "Tim's". Tim Horton's is the largest Canadian fast food restaurant franchise and Canadian cultural icon famous for its coffee and doughnuts.
The debunked urban legend that Tim's puts nicotine or other such addictive drugs in the coffee has sparked a cult-like following of caffeine addicts who regularly visit their Timmy Ho to get their fix.
ugh... my head is fucking killing me!! Gotta go see my Timmy Ho cause I'm jonesing for a double-double!