I wonder if anyone here has ever seen a pregnant woman. This would barely even qualify as having put on weight, much less pregnancy. Her back is in a curved line because she was side-hugged. Sheesh.
She is not a third wheel she is a disguised wingwoman! It's all part of her master plan. Minus the part where they start getting frisky on her back of course...
She even specifically asked for interlocked fingers. Can you believe how advanced these girls are? You don't start different grip positions until you are off age!
I think Afro tried to keep the yuri subtext down throughout the series, but having Rin get so friendly with Sakura was a mistake if he didn't want people to see Yurukyan as a Yuri series.