According to Dictionary.com , the term can range from a neutral description of a young person to an affectionate term for a romantic partner.
Traditionally, "tube" is a suffix used by video-sharing websites (most famously YouTube). In this specific context, it often points toward corners of the internet dedicated to viral videos or amateur content. morritas tubes
The plural morritas simply refers to a group of young women. 2. The Meaning of "Tubes" in Digital Culture According to Dictionary