Good question! It’s complicated! There are lotsa ways to do itl
On this tune, I’d do the whole slide on the D string. (this is from Otherside, for those reading)
I didn’t cover that specific marking (which is actually called a “scoop”) in the course. It’s often used for jazz articulations in horn charts, but I like using it on bass for slides that start in a vague non-specific location.
Love this. 
EDIT: I see all your questions were answered, but here’s this anyway! 