There is no easy way to explain this; there are a number of idioms that began to spread around the mid-eighties Madrid music and arts boom, referred to as "La Movida" (the move, the turbulence). The whole thing must be understood as a burst of freedom in Spain, a country which re-encountered democracy in 1978, after 40 years of Franco dictatorship. Suddenly, no more censorship (records like "Heroin" by Lou Reed, or X rated movies, things that could only be found in France or the UK before, were now freely available -there was also some/much indulgence with drugs), and there were live music and arts happenings all over the place. And the language reflected that, too.
The word "¡Toma!" pronounced like that, emphatically, was already in use, meaning: "You had it coming!" (the verb "tomar" means "to take"). Then, somehow mimicking the Cockney slang -as in just rhymes without any further meaning, like "trouble and strife", "bees and honey" or "Marks and Sparks"- , you could hear say "goma de Oklahoma" (gum from Oklahoma), or "costo de agosto" (cost from August); 'costo' and 'goma' being two of many words used meaning 'cannabis'. Depending on one's mood -or level of intoxication- one could enlarge the expression almost ad infinitum, e. g. : Toma Jeroma, pastillas de goma (que son buenas para la tos) = Here! Jeroma gumdrops (they're good for your cough). Some are harder to explain than others; "alucina, vecina" would literally mean: "hallucinate, neighbour" -female- (because the male neighbour in Spanish would be: vecino, -it wouldn't go so well with "alucina"-. The name of american singer Stevie Wonder, roughly mixed with "exactly" in Spanish, which is "efectivamente", would go "Efestivi wonder", meaning "You are right". A few books were published about La Movida, in case somebody wants to go deeper into the issue: "La Movida A-Z", "Madrid SÍ fue una fiesta (Madrid actually WAS a party)", and others.
Synonyms of toma, jeroma, pastillas de goma are toma goma jeroma movida spanish slang
Used in Spain as well
"Toma Jeroma, pastillas de goma (que son para la tos)"