You have to be sure to move smoothly up and down or else his testicles might get crushedhit by something , which kills the moment . Try laying on top of him and sliding forward and backwards using your arms and knees . This will be more comfortable for both of you as you won ' t be concerned about hurting the other . <| sep |> You ' re at iso 25 , 600 even at f 2 . 8 ? Wow that ' s extreme low light . You might want to consider the sigma 35 mm 1 . 4 to replace the 28 mm f 2 . 8 . That will get you down to iso 6 , 400 , which will look pretty good on the 6 D . It ' s not a cheap lens , but neither is changing systems and it will give you a better result than moving to sony and not upgrading your glass <| sep |> I got one of these yesterday , I had a 50 w istick forever and finally retired it . I had the original kbox and didn ' t like the coils but this seems much better . So far I like it but I ' m worried ultimately these will have shitty coils too . I hope the copper was worth it .