Why are my frogs hugging?

So, me and my sister, Kim, have had African dwarf frogs for the past 4 years. They each lived in their own little tanks with their own little snails (her's, named Pokey, abandoned it's shell and died about two years ago). Until I got a brilliant idea: our frogs could live together in a bigger tank and be friends. So today I go to the pet store, get a 2-ish gallon tank, some new rocks, a bridge for them to play around and hide under (they like to hide), and a plant. I set the tank up and put them in there. At first they each just sat there, scared to move. Then my frog, Nelson, decided to go meet Kim's frog, Jeremiah. That seemed to be the beginning of the end. Jeremiah grabbed onto Nelson's back and Nelson bolted. It seemed that Jeremiah wanted to kill Nelson. We all thought Jeremiah was attacking Nelson and so my Mom garbbed the nearest object, a sharp steak knife (the frogs live in the kitchen), and said to Kim "Here, incase you need to seperate them!" I called the pet store to ask the lady (who has her own frogs) if they were attacking or perhaps mateing. Not many answers there, just many possibilities, so I turned to the trusted internet. Through my research it seemed that Nelson was appropriately named having the male markings of white under his front arms. Jeremiah, not so much. Since Jeremiah was attacking Nelson and turned out to be a she, Kim renamed her Xena: warrior princess. As of now it seems that Nelson finally figured out what Xena wanted and is hugging her middle, trying to help her squeeze the eggs out. It has been quite the day of frog drama here at our house. Me and my brilliant ideas.