You're towing with a RAM right? (basing this on the key-fob you're holding). If that's the case, on my RAM, the plug cover is spring loaded. When you lift up on the cover, you plug the plug in and let the cover down on top and that's what "locks" it in. The plug has a catch on it that the cover sits in.
Other than that, I don't see anything overtly wrong with your plug. Just another little tip: I put a little dielectric grease in/on my plug, and that makes it a bit easier and protects the plug from corrosion.
2014 Jay Flight 28 BHBE
2015 RAM 2500 6.4L HEMI, Tradesman 4x4, 3.73
Blue Ox SwayPro (BXW 1503)
Upgraded from an REI internal frame backpack and a Eureka 1/2 dome tent!