To add a bit of information; As previously said, "ça baigne" is rarely used by any young adult. Note: when it's used it's often used in a more familiar way than "ça va" (less formal).

It can be told in the following contexts:

"Ça baigne, mon coco ?"<br>
"Ça baigne, mon vieux ?"<br>
"Ça baigne, mon frêre ?"

As you can see, the construction of the sentence differ a bit from a more formal "ça va".