It's never stated, and I doubt that it matters, since it's not a particularly sexual thing.
(Unless you get off on ripping out portion of your body and implanting it into other people for power-ups).
Regarding the newest chapter:
Dammit Violet. Things were going well for change and you blow it up to hell.
"Luis's girlfriend.....Riiiiiiiiight. If she's his entirely willing girlfriend, then I'm Queen of Monaco. I understand you might want to get your family to get along Violet, but considering your family history, it's not impossible. Hiding it from Satellizer as a "surprise" is also a dick move, considering the two's history of sexual abuse. Because they'll obviously kiss and make up right? No hard feelings right? Stupid, stupid Violet...or maybe just very naive.
I'm even more amazed however that they let him anywhere near Genetics Academy, much less attend, influential family or not.