I this what you were thinking of?
Can you imagine if all guys that masturbated "turned" gay? There would be nothing left for us ladies.
I think they were trying partially trying to scare straight guys that if they did "it" they might "turn" gay.
yychap.5pp.39-40MasturbationandHomosexuality***PRACTICES
Weakly giving in to sexual desires by masturbation will certainly not give you strength when faced with a situation tempting you to commit fornication—or even homosexuality. Just the opposite, it cultivates wrong thinking and wrong desire. In fact, masturbation can lead into homosexuality. In such instances the person, not satisfied with his lonely sexual activity, seeks a partner for mutual sex play.
This happens much more frequently than you may realize. Contrary to what many persons think, homosexuals are not born that way, but their homosexual behavior is learned. And often a person gets started when very young by playing with another’s sexual parts, and then engaging in homosexual acts. One young man relates: "When I was young, I had very little parental guidance. I was allowed to go my own way, and do my ‘own thing.’ It was when I was only about eight years old that my older cousins introduced me to homosexual acts. I found these pleasurable, and so continued the practice with them and later with others. Soon it was almost a daily activity. At first I had no realization of doing anything wrong. My parents had not given me any instruction regarding moral conduct, and I never confided in them. "We then lived in a Central American country. Later we moved to New York city, where I finished high school. I also continued homosexual practices. The schools and city are filled with homosexuals, so there were plenty of opportunities. As I grew older I realized that what I was doing was unnatural, and was not right. But I continued because I wanted to. These sex acts had become very enticing to me." The youth was "hooked" on the practices, and it was only after great effort that he was able to overcome them. What motivated him to change? It was a desire to please Jehovah God. When he understood that God views homosexual acts as "unnatural," and that He totally disapproves of them, the young man fought these practices until he had conquered them. God’s Word is very clear on this matter, saying: "Make no mistake: no fornicator or idolater, none who are guilty either of adultery or of homosexual perversion . . . will possess the kingdom of God."—1 Corinthians 6:9, 10, TheNewEnglishBible.