"Taking laxatives" is a euphemism for experimenting with illicit drugs. You see, as a child grows up, their parents expect them to encounter some really dangerous things - like cigarettes, alcohol etc. Therefore, there has to be a convenient way of mentioning
In australia, after exams party commonly involve binge drinking. when asked what's on the agenda for schoolies
, a child responds that they'll be taking laxatives. Laxatives, after all are pretty daring.
2 kids farewelling their parents for a week at schoolies full of "taking laxatives".
sezza: oi mate did you bring the laxatives (vb and coke)
girl2: yeah, we're gonna get so fried
sezza: i know, i love laxative's effects. it feels fantastic
girl2: bitch it's the best feeling ever. i love feeling the need to shit.
parents: you girls have fun. don't take too many laxatives!