Yellow is sometimes a challenge for me because I am tall and like petite girls, but we make it work. Either I will bend her WAY over and get down underneath her, or take her in front of a mirror and use a step (e.g. into the bathroom or some other small platform) for one of her legs to give her a boost.

Her on the bed and me standing is the most practical. I don't like both being on the bed, it's OK but you don't get the firm base to slam that shit the way you do while standing.