The ads were created in-house and ran in February. The advertising watchdog was hit with 20 complaints that argued the ad was offensive and overtly sexual.
There were also 14 complaints that challenged whether the ad was inappropriate for general display.
In response, Online Buddies, manhunt.net's operator, said the ad was first displayed next to the oldest gay bar in London and was displayed at a second location several metres away from London's largest gay club.
Online Buddies said it took into account the proximity of gay clubs, where they believed the ads were most likely to be seen by their target audience and that it ensured the ad was not within viewing distance of schools or business that provided children-based services.
Online Buddies argued that the image was not overtly sexual.
Primesight, the outdoor media owner which displayed the ad, said the ad first appeared in a location that carried a placement restriction for alcohol ads.
Once Primesight became aware that the ASA (Advertising Standards Authority) had received complaints, it moved the ad to another location, which was also not within viewing distance of schools.
It also sought advice and was advised the image was sexualised and likely to be investigated.
The same ad was running globally and Primesight thought the ad was not inappropriate and were therefore happy to run the campaign.
In its ruling, the ASA said it had noted that Online Buddies and Primesight had given the poster's location careful consideration, so as to avoid schools and businesses that provided children-based services.
The ASA ruled the ad was "sexually suggestive", rather than overtly sexual, and therefore required a placement restriction to prevent it from being displayed within 100 metres of schools.
As such a restriction had been put in place, the ASA concluded the ad was not socially irresponsible and the ad could continue to run.
Follow John Reynolds on Twitter @johnreynolds10
This article was first published on campaignlive.co.uk