It is very important to talk about feelings after a BDSM experience, especially one that pushes limits in some way (which should be talked about before and after) otherwise you will end up with confused emotions and he will end up potentially misreading your reactions to things. It may, for example, be that he did not think you enjoyed the butt plug which is why he is avoiding the issue...

Men in general (and I include most Doms in this) are not good at 'sharing'. I know this because I am one. Women need to share, to talk, to hug and do all the aftercare things whether it is vanilla sex or BDSM but men do not feel they need to so much and therefore assume that the woman does not either (yes, we are a selfish bunch of bastards as a gender). Its not really his fault, its a general thing that most of us have to fight and is hard to resist - one of those 'wired in instincts' like racism and homophobia which, if we are being absolutely honest with ourselves, everyone has to a certain extent and has to deal with.

So, I am afraid that you will probably have to make the first move and ask him if he does not mind talking about it. Once he realises that you want to talk about things he'll probably be happy to do it and will initiate it himself. Unfortunately, it is more vital to do this talking in a BDSM relationship as there is a greater capacity for physical and mental harm as a result of what we do.