One thing I've enjoyed is to ask her to swallow all but a small amount after a blowjob and then kiss me. A couple drops really isn't bad, even with post-nut clarity, and she can slowly increase the amount she gives me over time. Eventually you can get to the point where she's regularly giving you back your whole load, and you won't be repulsed by eating it out of her (disclaimer, I haven't quite gotten to this stage, so I can't say for sure that the method is effective). This works well for us since we usually finish with me in her mouth anyway because we both enjoy it and cleanup is easy.

I feel like this is a nice "gentle femdom" alternative to being tied up and forced to eat it. Instead of aggressively making me eat it, she's slowly training me to be a good cum eater for her. It can also be a fun game to decide to kiss afterwards, but she won't tell you in advance if she'll be saving any cum in her mouth or how much, leaving it all as a surprise for you.