I'm 19 years old and have been having sexual intercourse with my boyfriend of a year plus for quite some time now. We've both had great unforgettable experiences our share of orgasms and what not. The experience we had last night I wish we could both forget. We were having intercourse while I was on top of him and I reached the climax and orgasmed. Right after we both smelled something and realized I had pooped. It wasn't a drastic amount but still. It's the most embarrassing thing that has ever happened to me. He was a good sport and cleaned me and laughed about it. He held me close even after my hour long of crying. (He couldn't stop laughing even after that.) I just wanted to know why this would ever happen? I didn't need to go restroom or anything. It just happened and I didn't even notice it. Is this okay? Should I get myself checked? This sounds pretty unusual and I'm worried and embarrassed. I want an explanation. If there even is one. Thank you for your help!
This answer is going to require a diagram. Click the link below and open in a new window or tab.
Cross section of the female abdomen
I know the picture has a lot of labels, but try to locate the vagina on the diagram. Notice how it runs parallel to the rectum. In the body, the vagina is just ventral (in front of) to the rectum. They are very close together.
During sex, when the penis goes in, it pushes the vaginal walls outward (imagine your sock as you slip your foot into it). The British Medical Journal (BMJ) published a Dutch study that produced some MRIs of the body during sexual intercourse. To see how the penis fits in the vagina, look at THIS (it's a medical diagram in a highly respected journal, and does not carry an age restriction).
Imagine the pressure the penis exerts on your vagina and the surrounding structures. There is pressure being applied to your rectum as well (in certain sexual positions, particularly). If you look at that MRI (from the BMJ link), you can actually see how the rectum is compressed during penetration. If you have some residual feces in the rectum, it's likely the pressure from penetration actually pushed that last bit out.
Did you know it is COMMON for women to defecate during childbirth? The pressure of a baby emerging from the vagina also presses on the rectum and can force feces out during birth.
I'm sorry you felt so embarrassed, but consider yourself blessed to be with a guy who was a good sport throughout the incident. I hope you find the explanation thorough enough.
And for the geeks at home, this is probably the coolest citation ever! BMJ 1999;319:1596-1600 ( 18 December )