OP here. Maybe have Clark meet Bruce, Batman, and Matches separately. They all drive him nuts, and he has no idea they're all the same guy. Entirely up to you (or whoever wants to fill this) how Clark discovers their identity, whether on his own or Bruce eventually reveals himself to Clark. Or even whether Bruce is also unaware Clark is Superman. That's a lot of secret identities to play with! But when Clark does find out, the boys then proceed to have plenty of sexy times together. Maybe Clark enjoys a little roleplay and shyly requests Bruce to ravish him while in his Matches persona. Just go crazy with this prompt, nonny/ies. There can never be too much identity porn in the world. :D