It is a euphemism for " anal sex " in the sense presumably vaginal penetration as " 34 main route; and anal penetration as " alternative route ". The term was widely used in radio reports where it could not be very explicit because of the time protected for minors; and - if I remember correctly - it was coined by satirist Eduardo Javier " Cabito " Massa Alcantara.
In countries such as Argentina and Uruguay, the collection is a way that absorbs, collects and integrates traffic from one sector to another broader. This function is compared with women who are very ardent in sexual relationships and absorb the man completely. Going by collecting is a way of saying that he will have sex with a woman burning and absorbent. It is likely that this meaning might be different in other countries.
