My husband and sister in law went along with me too, and my sister in law, being the huge animal lover that she is, brought in some doggy treats as a gift for Hana-chan, the Shiba. The owner, Yota, spoke fluent English, and truly seemed to adore Hana-chan! Hana-chan is also one of the most well behaved and calm dogs I've come across - she sat quietly and happily when we were there. I guess you have to be calm when you are coming across new people all the time!
The street address for Bar Black Sheep is 2 Chome Dogenzaka, 渋谷区 Tokyo 150-0043, which you should just be able to copy into Google Maps if you have a smartphone and wifi access when you're travelling! Without those directions it can be a little tricky to find, as it is on the back streets of Shibuya. It is a small bar, and doesn't take reservations, but we didn't have any trouble just walking in.
We enjoyed our trip there, and felt like it was a very fun and welcoming bar with a great atmosphere - if you're in the area I definitely recommend checking it out if you have the time!
Also, the bar does have a Facebook page - and the picture credit from the photos in this article goes to there, as sadly I didn't have any pictures I took from the night we went!