He took her, lay with her, and violated her.
The Ohr Hachaim explains this possuk based on a Gemara in Horayos. The Gemara is discussing the story of Yael wife of Chever Hakeini. When Sisra declared war on Klal Yisroel, Devora was the Judge of Klal Yisroel and they won the war against them. Sisra escaped with his life and Yael invited him into her tent. She tricked him that she was his friend, and she fed him heavy food and wine. She then tired him out with her body, until he fell into a deep sleep, and she killed him. Chazal tell us that even when she was with him, she did not derive any pleasure from it, because any pleasure that is derived from an evil person is painful to righteous people.
Here too, although she was with him as a woman is with her husband, which would usually cause pleasure to the wife, in this case it was considered a violation and a cause of pain.
It was noticeable to all that she was under duress and she really did not want to live with Shechem and he had forced her into it.
