I used some obenauf's leather oil and just went at it with my hands, then used some clips to keep it down for 1 night and voila!
I think Drew mentioned in the past that he just soaked the collar (in water), to make it more pliable and just molded it from there (not 100% sure).
As for the second picture you linked, it actually looks like the guy has snaps to keep the collar down like that.














