OK, just by going through public sources, we can try to see what is it all about
:
1. When you go to Google, and type in site:gmentube.com, it's clear this domain name has been banned by Google, so site has no Organic traffic
2. If you go to Alexa, the stats look a bit different from the numbers you provided:
gmentube.com Site Overview
time on site is 24 seconds, which is not regular and a way too low, Alexa rank 109,614 which equals to very low amount of visitors daily, probably less than 1k visitors/day
comparing to site in the same niche
gaymaletube.com Site Overview
which has 3mins 24 seconds, what is 7 times difference in time spent on the site
Other than that, your site doesn't seem to have many video galleries and after making 20 clicks, I only see other jerk-sites and perhaps trafficshop/trafficholder landing pages. so it's not clear what are you providing to your visitors in the end or how you are sending them to tube sites, as far as I know tubes do not pay for skimmed/blind traffic.
but the question remains, how such a small site could have sent 1.6mln visitors in this short time period?