My family moved to PA in the late late 90s, right after my dad retired. At that time, my younger brothers and I were homeschooling. Though the Catholic homeschool group was strong, the kids were either young, middle-school aged women, or babies. The only homeschool group that had an abundance of young men was the protestant group. Not only were the guys in the protestant homeschool group guys, but they had the added bonus of being musicians, and Star Wars fans. Naturally, we fit right in.
After the first year of homeschooling in PA, I attended a Catholic High School until Junior year. Junior year I 'dropped out' and finished my last two years of High School adidactically (huh?). During those last two years, my friendship with the protestant homeschoolers grew considerably. In fact, out of most of my friends in High School, the protestant guys are the only ones I still talk with on a regular basis.
All of us hit college about the same time. Most of the local homeschoolers went to PSU, and I went to Christendom.
When my buddies went to Penn State, some of them started attending bible studies on campus. When I'd come home from fall and spring break their university would still be in session. So, I'd go with them to the bible studies.
I didn't go because I was doubting or exploring my faith. I eagerly signed up for I saw it as an opportunity for evangelization.
When I'd show up at these bible studies I'd be incognito. I wouldn't reveal to anyone (and neither would my friend, initially), that I was Catholic. This allowed me to participate while avoiding confrontation on matters of Church history, indulgences, being the whore of Babylon, and other such things.
Before I go on, you have to understand that protestant bible studies work differently than Catholic bible studies. Their bible study groups are not a form of lectio divina. Instead, they just straight up read, pray, and have a hearty discussion. For a visiting Catholic among discussing protestants this format was a beautiful avenue for Truth!
So I'd go, and I'd listen to what they had to say about the bible. While listening, I'd try to figure out the best way to present the Catholic position, or lead them to the Catholic position on a particular scriptural passage without revealing my allegiance! I had to combine socratic questioning and tact. This combination, once prefected, ended up being a very useful tool for getting the Truth out there. Quite frequently Catholic scriptural interpretation disguised as an innocent personal interpretation, would get many head nods and agreement!
Sometimes, though, sometimes there was not much agreement at all. There were times where my Catholicism was painfully evident, and there was no way to lead to the truth. Those were the times when such things were brought up like contraception, or the Capernaum discourse in John 6.
You might not know this (I'm sure you do), but the Eucharist and Contraception are two of the most polarizing issues between Catholics and protestants. Our disagreement is incredibly stark, and there is little commonality.
At that point, discussing contraception or the Eucharist, my hand would be revealed, and they always just wanted to agree to disagree. Oh well.
I thoroughly enjoyed these infiltrations of Protestant Bible studies. If it were up to me, I'd still be doing it, trying to plant seeds! Work, position, and other demands require I temper the spirit of my infiltration evangelization. Some day, though, I hope to get my wife in on the practice, and start it up again at local protestant bible studies.
It was incredibly rewarding while it lasted, and it encouraged me to be precise and tactful in how I presented our theology to our seperated brethren.