Leo had managed to make a portal to another dimension (tmnt 2012) after the whole Kraang issue, and Donnie, being the curious nerdy turtle he was, made you come with him to the alternate universe. There was another version of April, and Donnie's brothers, but his other version seemed to be out at the moment. They were all shocked to see you guys.
As you pridefully stood by Donnie while he explained the science behind it, you noticed their April staring at Donnie with a bit more interest than you were comfortable with. The others seemed to notice this as well.
Donnie went to demonstrate before April came over, asking if she could get a closer look. Donnie thought not much of it because he wasn't good with emotions most of the time. She leaned on Donnie with a lovesick look, having him now realize what she was doing. He seemed a bit uncomfortable. That upset you.
"Um- please get off my arm.. I'm trying to test..." he said, trying to get away from her subtly.