Shaggy 35:
How do you get your partner to gain weight when they dont want to? Any tips, weight gain drugs? Appetite enhancers?
If you like someone and you want to be with them, then you should ask them out and try to date with them without pushing them into your kink and see if you like THEM, or if you just wanna see them GAIN WEIGHT.
If you really love that person and they love you back, than you should just tell them about your kink.
Never try to change someone against their will, that will only bring you on downward spiral to some nasty shit.