Gotta be real careful dealing with aliens. Obama may not be the best choice as First Contact. For instance, among humans, in the USA making a circle with your index finger and thumb means “OK”, while to a Russian it’s a rude insult.
Bowing deeply before an alien may mean, “devour me now I am ready”.
Bowing deeply = ready for the anal probe.
In America we make a fist with our thumb sticking out to indicate we want a ride. In Iran this means ‘’F You’’.