I did that once to a ex, she came like crazy. Later she said that was the hottest thing a guy ever did to her.
Mmmmmmmm creampie! OH you just do it don't even think. Once you get started it great. Weather your eating your cum from her pussy or your hand, my cum is good. Man I want a JB from your wife. So she can do that for me.
Have done this many times and never had any complaints honestly usually it is just enough to send her over the edge.
I have surprised a lot of women in my life with another orgasm after intercourse by going down on them after I just came in them. None have ever experienced that before and in m y time in the 60's and 70's, even regular oral sex was considered to be gay and many guys would not go down on a girl because it was not manly. Times have changed a lot. I even went down on girls after other guys have ejaculated in them. Goes with the territory when you are into various forms or group sex and an open relationship.