Boy Name Ender
Male Name Ender, Kun
noun, suffix
Add this to the end of someone's name, it's like saying ______buddy. It's generally used as a name ender (like さん) for boys and young men. Don't use this on people who are higher ranked than you (socially or literally). As in, you wouldn't use it on your boss. Use it on your younger male subordinates as well as boys who aren't adults yet.
The reading is the same as the one you learned with the kanji (on'yomi), probably because it usually is attached to other words (aka names, like こういち君) making it act more like jukugo words do.
マイケル君
Michael-kun
山田君
Yamada-kun
たかし君
Takashi-kun
マイケル君には兄弟がいません。
Michael has no brothers.
田中君、今日も元気そうだね。
Tanaka-kun, you look well today.
山下先生は、男女両方の学生に「〜君」を付けます。
Yamashita-sensei calls both male and female students with "-kun."