ADvice on bi-sex?

[Vikingboy]

I'm working on a multi-part story that will end up with a Dom Male involved with a switch Female and a sub male. The payoff will be a first time bi-sex experience for the Dom with the sub male, with the help of the switch female. I'm stuck on getting from the tease to the payoff. If someone would like to help with this via PM or private email, I'd appreciate it.

Thanks in advance