It sounds like this may be a show of dominance. Is your dog showing aggression doing this, or does it merely want attention?
If it is showing aggression, try asserting your dominance.
see:
http://www.trainpetdog.com/boxer_articles.html
http://www.bcrescue.org/dominancetest.html
http://www.k9web.com/dog-faqs/behavior.html#principles_behind_dominance
they stand, sit, lie down, and even stand upside down.
Sit down
yes. but some cant sit or stand for 30 minutes
A lap.
They can do it doesn't matter if you sit stand or lie down.
they stand in the U.S (occasionally they sit down)
people stand up and sit down
* you sit down and talk never stand
The cast of Stand Ups Sit Down - 2013 includes: Wil Anderson as himself Rove McManus as himself
sit stand
After you have tamed it, right click. It should sit down until you tell it to stand up.
tell them to get it off your chest and sit down and have an honest conversation with them or ignore them