I don't recall reading anything on this topic before, but the idea that your "parts" are inferior to the other gender's is a really good idea which can be used for either way (male or female subs)
For me, I was to immagine my clit was a teeny dick, and I could only rub as a guy would, whihc meant no pussy play, no breasts, leaving only my clit to play with or "my other hole" Embarassed all the while i was doing this i was to carry out a conversation, in which he continuosuly made comments of how it was a shame i couldn't jack off like he could, or wrap my fingers around such a teeny little penis like he could his big dick. Being the untrained sub that I am, as I got hornier I began to beg my master to allow me to rub or play with my pussy. I was reminded that I should not be thinking of being fucked but rather I shoud think of wanting to fuck things. I was allowed to watch clips of a guy jacking off so I could see/immagine how it should be done if my clit was only bigger.
Finally, he allowed me to pull on the lips around my pussy hole, like I was playing with my balls, which was a great relief for my aching pussy.
Thinking of, seeing, and hearing how my little girly-dick was so inferior to his was a big turn on, and I thank my master for making me ache and burn so badly.(I just hope he allows me to return the favor one of these days Wink ) As a further note, I thought you may be pleased to know that he says that as I have pleased him so far he might continue my training, by allowing me to learn how to pee standing up like a man, so that I may have the humilliation if I miss and get myself instead.