I think this series is really making me appreciate pants (taking them off, to be precise). They're pretty erotic in their own way, arguably moreso than the skirt lifts.
the bank lady and the trap are sister and brother : same hair color , same eye color .
the funny thing is that the artist already made a book with only boys show their under-wears , you can search google for its title : 嫌な顔されながらおパンツ見せてもらいたい本男子部 .