What is Vallis?
1.
a dirty mexican
Suze: hey malcum your such a vallis
Malcum: shut up suze i'm not dirty im just a mexican
See
2.
What you call a boy who can not do anything without his mumma's help and who thinks he's really good at European Handball but actually sucks like shit
When a girl rejects you, she would usually say," You're such a (John)Vallis!"