Sounds like he's lazy if he wants you to do all the leg work for something HE wants to do. 😁
I googled "breast damage from caning"
Try these:
http://www.perthspanking.info/articles/CS_25-AUG-2008.html
http://www.asksubmissann.com/2007/01/24/marks-causes-and-after-care/
http://www.subdominion.org/inside/refrence/refbreast.htm
http://www.submissiveguide.com/encyclopedia/breast-torture/
http://bdsmplayground.tumblr.com/post/43467006587/spanking-safety
https://thekinkyworldofvile.wordpress.com/2012/09/16/impact-play-and-safety/
http://www.bdsmerotic.com/boards/viewtopic.php?f=8&t=429
There is actually much more!
Just remember, YOUR breasts will hurt a lot more than his from caning because you have thinner skin and glandular breast tissue underneath while he has thicker skin on his chest, hair and muscle underneath.
One more thing. Just to get you up to speed with my husband and my experiences in S&M; when our daughters were younger we had to watch some of our activities because we couldn't go around marking each other (we're switches) when the girls were younger and living at home so we had to wait until they were at sleep-away camp for the real hard games. The screaming was sometimes quite loud. Besides, the family would frequently go around the house nude and being covered up all of a sudden would have meant something was out of the ordinary.