Side boob is a view of the female breast seen from a side; generally under loosely-fitting clothes. It's very titillating and sexual without showing any overt nudity. The word has been added to the Oxford dictionary.

“侧露胸”是从侧面看到的女性胸部，通常因为衣服太宽松而走光。“侧露胸”没有公然裸露，却异常性感勾魂。这个词已经被收录到牛津词典中。

For example:

There are so many side boobs at the Los Angeles awards show!

洛杉矶的颁奖礼上有好多“侧露胸”啊！