Oh, yeah, I had to look that one up in the Urban Dictionary:
semper ubi sub ubi
Origin: Latin
An admonition given in Latin classes in English speaking countries. Its literal translation, if not in English, is nonsensical, but in English is “Never Where Under Where.” SUSU is often found as graffiti in the more educative schools.
Semper ubi sub ubi - Anonymous
**Author leaves giggling**