It is one of several nicknames given to a highly addictive designer recreational drug that is actually known as '2C-B', which in English is pronounced as 'tu ci-bi', and which gave rise to the apocope 'tusi'.
It is one of the names with which a very potent and addictive synthetic drug is designated. It can cause death. It is a very dangerous multi-drug cocktail. It can be LSD mixture, or ketamine and ecstasy. It is also known as pink cocaine.
"Tusi", is the name given to a synthetic and very addictive substance, whose consumption represents serious risks to mental health.