Yup, I know exactly what you mean. Sometimes the 'in between ache' is worse when I don't talk or get out what I want to say in my session. So I'm pretty conscious of that and it's a good motivator halfway through the session.
I also see my T twice a week, and can text/call in between sessions, and that has helped too. But so far I haven't come up with anything that completely eradicates the longing.