A good rule of thumb is if "a side" of the boob is showing, any side, then to someone somewhere -- it's sideboob.
Case in point: all the shots of the inner side of one boob, like through a partially-open shirt
(paparazzi love these).
or
the outer side of one boob + the inner side of the other boob in same shot. (both sides count)
or
well you get the idea.
Places to look for sideboob?
Always good sideboob to be had at the beach or pool.
