Recline foot extended.
Then pull the rn forward just a bit.
It's a matter of moving the seat forward enough so that the buckle (male end) lines up to the stalk (female end) which is fixed and angled slightly forward.
If you don't line things up just right, the seatbelt gets caught in the latch plate, either getting crinkled or just plain stuck.
If it's easier for you to let things get crinkled/stuck and *then* pull the rn forward until things align then do that. At that point you'd be able to fix te crinkle by working some slack back into the belt (leave your belt unlocked until the very end -- like until things are aligned and the belt is worked very tight) get your knee in the seat ... Little bounce pulling belt tighter... little bounce... tighter...
It goes in rock solid, just takes a little bit of fussy work.