I had a double special once as well....found that the energy of having 2 girls that were, well, acting the part was actually a turn off.
They chatted to each other the whole time during the massage, then started talking dirty at the release. It still worked, but was kind of cheesy. it was like they were chatting over the water cooler, rather than my very special and beautiful member.
I've been in some threesomes in my non - paying sex life, and the energy is out of this world....if you could find a good session that had the energy and excitement of things a little different, rather than the aforementioned another day at the office hand job - I'd sign up for sure.