Not sure how much longer this will be online as, apparently, WB is trying to get this Suicide Squad scene taken down at YouTube and other video hosting sites.
Normally set video is not taken down as it's in the full view of the public (and the movie is shooting in a different country than the U.S.); however, it's unclear where this particular scene was shot and may be leaked production video (or a worker on set illegally filmed it).
That said, the scene features Jared Leto as the Joker arguing with Margot Robbie about something. Quinn has a gun out, with the Joker not too concerned. A trucker with a tire iron approaches the two, with Quinn shooting the man. Joker and Quinn then go back to arguing without much thought about the man. Joker seems to motion to Quinn to "go ahead do it" or "come on, come, come on." The two continue to argue for a bit, with Joker eventually disarming Harley, and then Joker puts the gun to his own head before putting the gun into his front pants and slapping Harley Quinn and getting into his vehicle.
Correct me if I'm wrong, but Joker might also urinate on Quinn before getting into his car.
It also appears that Joker does have tattoos - at least on his stomach.
Update: Jared Leto Joker tattoos confirmed.
"Suicide Squad" has an August 5, 2016 release date directed by David Ayer starring Will Smith as Deadshot, Jared Leto as the Joker, Margot Robbie as Harley Quinn, Cara Delevingne as Enchantress, Jai Courtney as Boomerang, Joel Kinnaman as Rick Flag, Viola Davis as Amanda Waller, Adam Beach as Slipknot, Karen Fukuhara as Katana, Adewale Akinnuoye-Agbaje as Killer Croc, Jay Hernandez as El Diablo, and Scott Eastwood in an unknown role.