The cases 9 and 19 where a negative experience for the boy and are therefore not included in JUMIMA. They can be read in the article linked below or in the book.
Source: Rind, B. Gay and Bisexual Adolescent Boys’ Sexual Experiences With Men: An Empirical Examination of Psychological Correlates in a Nonclinical Sample. Arch Sex Behav 30, 345–368 (2001). https://doi.org/10.1023/A:1010210630788
Case 12 (boy 16, man 21). Met at a science fiction club; became friends. “He was like an older brother to me; he came out to me as bisexual; said he loved me and asked how I felt; no problem for me; not repelled so I asked lots of questions. First time we were together we were not intimate but he just touched my chest. I went over to his house a lot and eventually he gave me a massage; later became sexual; he was active with masturbation and oral sex; very pleasurable but I tried to make myself not ejaculate because I knew society said it was wrong. Happened seven more times. I decided I needed to be heterosexual so we stopped seeing each other. He was afraid that maybe he was just using me for sex and he wanted me to be emotionally with him; overall it was a very enjoyable experience but I knew IGay and Bisexual Adolescent Boys’ Sexual Experiences With Men couldn’t tell anyone about it. Only later in college when I came into contact with gay culture did I see I could label myself as gay.”