Grammar Rollercoaster is a technique used by psychologists to make a point or prove something with combined thoughts of a child, teen and an adult (combining how a child, teen and adult would think). It involves little satire which may allow the use of reverse psychology. Grollercoastering is linked to anchoring in Neuro-linguistic programming. Check anchoring for more information.
Giving an example of Grollercoaster can only be provided by someone who uses this technique. However, learning this technique yourself will allow you to spot it being used. It is, however, said to take a few months to master this technique.