I used to practice a lot of (non nude) life drawing in high school. I remember my teacher would make a student sit up for a period of time on a chair while my class mates drew. He’d try and challenge us sometimes by making us draw with a continuous line without lifting our pencil or we’d have to just look at the subject and not at our paper. I found these to be really great drawing exercises.
They help you learn proportions of the body and help you draw the human body a lot quicker.
I recently found a nearby life drawing classes ( nude). It cost 15 bucks for a drawing session for 2 hours. The model we had for the evening was amazing. She was very aware of her body and gave very dynamic, different and challenging poses. She was even aware that the artists were sitting in a semi-circle so she tried to give everyone great angles and poses. The lighting that was set up was pretty good to give good shadow. The first couple of poses were 1 minute poses for gestures and warm ups…. OMG 1 minute poses are very hard to quickly draw but its about getting the gesture and right proportions and no detail. But I found doing those 1 minute gesture poses made the 5 minute and 15 minute poses feel so much longer and I was able to draw a lot of detail in 15 minutes. I highly recommend finding a local life drawing drop in class near you. They are usually held at art schools ( and you necessarily have to be attending that school to go) or there are non-profitable art associations ( which is what I went to.)
If there are no local life drawing classes near you there are great resources on the internet. I found this one on youtube. They have multiple life drawing videos for free!
So what are you waiting for ?
Start practicing your life drawing skills!