The story
Ts is an initialism of Talwin, a brand name for pentazocine; blues derives from the fact that tripelennamine tablets are usually blue in color.
Etymology from Wiktionary, CC BY-SA 4.0.
Ts and blues
Today it means: The combination of the drugs pentazocine (an opioid analgesic) and tripelennamine (an antihistamine), used for recreational purposes due to its euphoric effect in the 1970s and 1980s. Full definition →