See my post about the plastic insert.
They are a simple horseshoe device and cost pennies, but if you dont check them they can break up.
dont you do the pull forward in a low gear?
Not yet dropped one, but it did come close while I was learning. I think it helps not having run-up rails on my unit. now I have to back under, and lift it up with the suspension before coupling. I can’t just ram the unit under and hope like some.
The auto box helps. Can’t get it too wrong with R and D on the dash 
allikat:
Not yet dropped one, but it did come close
Try some fibre 
i hitched up a trailer last week and the pin wasnt in properly.i didnt hear it click when i coupled up,sometimes i dont if its noisy where i am.i pulled forward to check,all seemed fine.when i got out to put the dogclip on i noticed a 5 inch gap between the fifth wheel and trailer,good job i spotted that 
stevetel you can see that we have all dropped one. I have dropped 2 and nothing came of it ,although i worried my self sick and my head was full of mental agrivation giving myself grief and self doubt, in a week or two it will be water under the bridge