For some reason, I felt compelled to make an account to elaborate on this. Just to be clear, my knowledge of Japanese as a language is at a beginner level.
Starting from the beginning, Japanese as a language is largely phonetic, with most hirigana and katakana "representing" consonant and vowel pairs. The only one's that don't are し (shi),つ (tsu), and ん (n), unless I'm missing some. An easy way to think of it is that each individual character in Japanese is treated the same way a sylable would be treated in English. That's why, if you listen to Japanese cadence, they emphasize things strangely compared to what we are used to as (presumably) westerners, with the beginning of each individual character stressed. Each of these characters takes roughly the same amount of time to pronounce in conversation, which can make the language sound kind of... mathematical?? If that makes sense. Or maybe formulaic is a better word; in any case, once you know the rules Japanese is remarkably straightforward in terms of pronounciation and syntax.
Chris, being a name, and clitorus, being a loan word, are spelled using katakana (clitorus might have a kanji too but I wouldn't be able to tell you what it was). They look like this:
クリス
クリトロス
Both share the same initial two katakana, as well as the final katakana. Which I guess makes them similar in a way. Regardless, the characters make a nickname based on (presumed) perverseness and Chris' name.
Rather than thinking of it as a combination of the two words, it's more appropriate to think of it as Japanese word play. Because the nickname クリ would be both Chris' name and a shortened form of clitorus, so saying it with one meaning could call to mind the other meaning depending on who you were talking to. Or, more accurately, it would mean both at the same time. It's similar to Okami, which means both Big God as well as being the pronounciation of the Japanese word for wolf (trivia).
Homophone is the word I'm looking for. Japan loves the stuff, which is why you get things that say "written as _____ but pronounced as _____" and it's also why new students write their names on the board when they are introduced to the class, because there are multiple ways of getting the same sound combination, and kanji can have multiple pronounciation.
*deep breath*
For a couple of reasons, these jokes don't transfer well or easily to English. In this particular instance, the fact that we differentiate between r's and l's means that essentially the original joke can't exist in English. "Kri" is faithful to the pronounciation, but doesn't convey the joke. "Krit" is inelegant, but manages to combine the two words, essentially, and thus carries the original joke meaning across, even if it's a bit cumbersome. "Chrit" would probably be a more accurate alternative, but that just looks funky to me for some reason.
Also, since this is my first post on this website I just wanted to say thanks and good luck to the translation team for agreeing to translate Majikoi S and, especially, for already translating Majikoi proper. I definitely appreciate the hard work you guys are doing, Majikoi is a fantastic series and I am enjoying your translations immensely.