In recent years a new, extreme sub-culture of sex and drugs has become a way of life for a growing minority of gay men. The so-called chemsex scene involves an unholy trinity of drugs \u2013 Mephedrone, GHB/GBL and Crystal Meth \u2013 and together they can keep men awake for days. These relatively new drugs are taken to enhance one thing in particular - sex. Mobeen Azar travels to San Francisco - one of the first cities to see the \u2018party and play\u2019 scene emerge - and London, where chemsex is a relatively new phenomenon and speaks frankly to men involved in the lifestyle.