The rolling r (and rr)

[Elaina]

I think you also have to almost close your throat or curve your tongue to make a bridge and exhale so that the tip of your tongue flaps....

Sounds silly, doesn't it?

[Planet hopper]

Yep, right
I aimed at describing the initial position. Using the throat may result in learners making the sound the french way.

A famous tongue twister to practice it:

El perro de San Roque no tiene rabo por que Ramón Ramirez se lo ha cortado...