Originally from å°ć (toutoi), meaning
precious, valuable or priceless, it became Japanese internet slang "ć¦ćć¦ć (or ć¦ćć¦ć)" roughly meaning someone else's actions are wholesome, or
precious.
Popularised in the west by subtitled V-Tuber clips, where it was used typically during moments where the V-Tubers were acting affectionate to one another; this hard to translate word was often simply romanised. This resulted in several spellings, the most
popular of which seems to be "TeeTee", whith other variant such as: tee-tee, tee tee, tei-tei, TT and te-te.