Before meeting my hubby, I could take pretty big, but not usually all of it. Since meeting my husband, and the countless number of men I have been with, I have been able to take more and more as time has gone on. I have a small pussy. But It does stretch quite well. When I met my hubby I couldn't take his fist in me, but now I can. I have always been able to take length pretty well, but for the longest time I could only take so much. In the last 6 years, though, I have been able to take longer and longer cocks because my hubby has helped by using different toys in me, suck as leeks, cucumbers, and other long cylindrical objects.
I will admit that the more excited I am the more my pussy will accept. And the more often a woman's pussy is used the more it can take. And I agree, the more relaxed you are, the more you can take as well.