I use this technique when teaching a topic significant to missionary teaching, like the plan of salvation or baptism. AFTER some instruction on a scripture passage or gospel principle, students are assigned into groups of three. Students read the same passage of scripture together as if this was a real missionary lesson. One person is the "nonmember," and the other two are the missionaries. Missionaries make an effort to teach the principles found in the passage to the nonmember. The nonmember asks questions to help missionaries teach ideas that were unclear. You may need to instruct nonmembers that they are playing a sincere seeker of truth, not a hater.
Don't use this on particularly challenging or difficult passages, but use it to teach simple gospel truths, such as one that a missionary might encounter. It's great for passages on the Atonement or baptism.
Sometimes I tell my students that this is a practice for their chance to teach the Ultimate Investigator: me. After the lessons are done, I ask "nonmembers" who had an exceptional set of "missionaries". Then I have those exceptional missionaries come up to the front and demonstrate their skills to the entire class, with me playing the role of nonmember. I have found that advising students they may be called up front to teach me prevents most shenanigans.