Can't believe no on'es brought this scene up yet! *slight spoiler*
i started watching this about 45 mins in, but i'm pretty sure it was the first time Laura goes to see the women about possibly having a reading about her daughter,...well the old sis goes into her spell and starts saying "Yes! Yes! Yes!" and grabbing her breasts! wtf?
i couldn't figure out what that had to do with the husband then receiving his warning. Maybe she was saying yes to the spirit? but it certainly seemed like she was having invisible sex. sorry....
I loved it though! great old classic horror-thriller with the incomparable Donald Sutherland