What you do as a tribute towards the dead; usually done either in the military or in modern culture like E-Dubble. Its usage with that last one was due to the game "Call of Duty: Advanced Warfare."
Person 1) "Dude, E-Dubble is dead! D:"
Person 2) "Sheit, well, time to pay respects."
By Sal
Press F To Pay Respect
It is a (semi-funny) response, seen a lot on social media like reddit, for example for someone with no chance of surviving a gaming battle due to enemy superior force , originally from 2014 first-person shooter Call of Duty: Advanced Warfare. Quoting know your meme :
"Press F (X) to Pay Respects is an action prompt featured in a quick time event from the 2014 first-person shooter Call of Duty: Advanced Warfare. Upon the release of the game in November 2014, many players of the game mocked the funeral cutscene for its forced element of interactivity that seemed out-of-place at a memorial service."