I have found that after sexual intercourse some women were too sensitive so I've NOT experience the cum issue. While not exactly on topic, what I have experienced more than once while going down on a woman was her arousal to an orgasm together with an uncontrollable ejaculation. This clear fluid is from the urethral sponge. Some partners find ejaculation very exciting, while others may be alarmed. Personally, I find this act very erotic.
One problem with this was I had to halt the licking I was doing. To replace the stimulation with your mouth, I planned ahead with either my fingers or a sex toy. An interruption on the verge of orgasm could be very disappointing so I was sure to have a toy so I didn't miss a beat.