Yea, definitely, but for me, bending a straight person gradually into the realm of bi sex is more exciting and challenging accomplishment.
The fun and thrill in this seems to be more compelling.
Here the only guy that I knew who was up for this at short notice was a friend of a friend who was gay. He had the opinion that all men were gay they just did not know it, and that he could 'permanently' convert me from being bi.
So the opportunity to disrupt a hetero couple, plant the seed of doubt that this was actually a regular real event, perform in front of my female partner, and do it all bare-back, was too much to pass over. She agreed to all of his conditions, luckily I did too but she just became fixated upon this happening.
A lot of 'straight' guys are surprisingly responsive to pre-op T-Girls. They are adamant they are 'STRAIGHT' even when they are bedding a woman above the waist and a man below. Just relax, and chill it's OK to be like that. and to like that ambiguity/variety/opportunity. Once the blood moves from large head to little head they become much less fussy about what goes where as long as it feels nice.
We're back to Kinsey and it being a continuum based upon genetics, culture and opportunity.
With subs you can see a bi side and them wanting you to bring it out for them. If you are doing it then they are not responsible. It's like chiselling out the statue from the block of marble.