If I have to spray a body indoors, I head to the bathroom, rinse the bathtub and all the surrounding tiles with water, put the body in a cardboard box and spray it. Immediately after I am done, I rinse away any overspray, rub everything clean and open the window. In the case of multi-color paintjobs, make sure to rinse the tub and tiles everytime you leave the paint to dry.
That's the last body I did this way, did not turn out too bad.