1) take in your hands Titan Launcher
2) switch your Titan Launcher to Top fire mode (F-button )
3) go to prone (Z-key)
You will see that after the player’s character goes to prone, he will rise automatically and again and again take your Titan launcher in your hands.
video example after fire:
https://www.youtube.com/watch?v=Wa_p_s2wGN4