My lady has no reservations about finishing a blowjob by swallowing. She even tells me that she thinks it's hot to taste herself on me when finishes me after sex.
One of the easiest ways that this comes to fruition is when we are in the 69 position (her on top). If either of you goes to orgasm, it's not really the easiest position to get out of quickly, so finishing an orgasm orally just kind of "works" especially if you can scarcely say anything with a girl straddling and grinding your mouth. When we 69, my lady likes to take all but the tip of me out of her mouth and rub me on her lips and tongue while she strokes me through it. I end up cuming half in her mouth and half all around her mouth; usually while she's cuming too (she says this tends to push her over the edge). For a while she kept a towel close at hand (always a good idea) because she didn't want me to see what she did as she often criticizes modern pornography for using facial orgasms as a demeaning act towards women; which I tend to agree with. But after a bit, I asked her "Do you like it?" to which she replied, "A lot..." "So do I, so screw everything else."
Now we're both happier. After all... I like it when she cums in my mouth on my face too.
~Steve