Guitar Hero Aerosmith
49 Achievements
1,000
15-20h
Xbox 360
Sick as a Dog
You earned a 5 star rating on a song on Medium or harder
25
How to unlock the Sick as a Dog achievement in Guitar Hero Aerosmith - Definitive Guide
Again not terribly difficult 5* rating requires greater than 95% hit rate, most of the early songs are quite easy to get this on.
For this achievement you have to hit a high percentage of notes (95% or more, I think). You should get this on the first tier whilst going for I Don't Want to Miss a Thing. Alternatively, you can get it on LIVE with a friend whilst going for the co-op achievements.