“NAFCU got asked to provide a witness,” Roche explained. “NAFCU knew that our credit union has had EMV credit cards on the streets – it's been about four years now – and that we were well on our way to reissuing debit cards. They asked our credit union to testify because they knew I had some expertise in the area.”

The Alexandria, Va.-based State Department FCU has $1.7 billion in assets and 71,000 members.

Wood said her invite came when the Pennsylvania Credit Union Association heard Senator Pat Toomey's (R-Penn.) office wanted witnesses and floated her name. The Dubois, Penn.-based Timberland FCU has $59 million in assets and 9,800 members.

2. Be prepared to drop everything. “One thing about testifying is sometimes there are times we can give a few weeks' notice and sometimes it's a few days' notice,” Thaler said. Often it's a week, he said.

“Logistically there are challenges of travel and getting someone in here that works on their schedule … asking them to basically take off for a few days between traveling and coming here to prep and testifying and traveling back home is not the easiest thing in the world,” he added.

3. It's a team effort. The organization that got you a congressional invite will likely help craft your testimony and help you handle the committee's questions.

“A testimony has broader policy issues and questions and information, but then we also try to get real-life examples from the institution that's testifying, and maybe even other institutions,” Thaler explained. “Because one of the more effective measures on Capitol Hill are the personal stories.”

Hearings are often 90 minutes to two and a half hours long, and witness panels typically include three to seven people, he noted. Often, each witness gets five minutes to read testimony and then the committee asks questions. Witnesses usually come to town a day or two early to prepare. Roche, for example, spent the day before her hearing at NAFCU preparing for questions and practicing reading her testimony.

4. You probably won't get grilled. “At first it was a little intimidating,” Wood said of the questioning. “But then listening to their questions, they just really wanted to know my perspective and the panel's perspective in general – how we deal with the regulatory burden on a day-to-day basis and what really happens when the rubber hits the road.”

There's another reason things often stay cordial: Out of deference, committee members often avoid beating a witness up if he or she is from a committee member's district, Thaler said.

5. You won't be alone. Thaler said his team often escorts witnesses everywhere.

“Oftentimes we will go in and visit the chairman of the committee or the members of the committee before they testify so they've met the folks,” he added.

He or another staffer also usually sits right behind witnesses during the hearing so he can hand them notes or discreetly give reminders, he said.

6. You'll probably want to do it again. Testifying before Congress can be nerve-wracking, but both Wood and Roche said they're grateful for the chance to participate.

“Your mind tries to focus on, 'Oh my goodness, I'm scared,'” Wood said. “But then you have to step back and go, 'You know, this is a really cool experience.' Take it all in.”