Most times, the initial short poses are really just a warm-up to the second half of the evening, when we move to 10- and 15-minute poses. My favourite is often the last pose of the evening, when the model lets her haird down (literally) and uses a prop or costume. I did this one in direct watercolour, only using a watercolour pencil to hint at the chair and reinforce some of the creases and patterns in the dress.
I'll spare you the one-minute poses, but here are a few 5- and 10-minutes. Interestingly, the fives are better than the ten I think. It's a balance between having enough time to get the shapes and proportions and having too much time to start doubting myself!!