A swim coach at a pool wears a speedo.
A man mentions hosting wet t-shirt contests.
Women are portrayed as sexual objects throughout the entire movie.
Two women are propped up on a table in short skirts while a man judges their body.
On various occasions, we see the family's male dog humping a large, stuffed duck toy (at one point, the kids see this and call it "wrestling"). That includes it doing so in fast forward motion, and while "seated" back in a chair with the toy on top of him.
Twice, Michael and his wife have sex in fast forward, but all you see in the shadow on the wall. Which is him humping her (a shadow of a dog is also briefly shown humping Michael) This only lasts a few seconds.
The remote takes Michael and Morty to the "making of" his life, and they end up in a room with Michael's parents having sex, but you don't see anything except the sheets moving. When Michael tries to get himself out of that room, he fast forwards to his birth.
Michael states that he and Morty are inside his mother's vagina, though there is nothing anatomical about the scene. He and Morty are standing in a dark room and there is light coming through a slit in the "wall."
You see a doctor's hands open the slit wider and then his face is revealed. Again, this is mostly innuendo and does not actually show a woman's vagina.
Donna wears a Pocahontas costume while playing with her son, and then offers to "play with" her husband at night while wearing the costume, implying sex.
When Samantha is 14, Michael is shocked to see her grown up and makes a remark about when she got her boobs, prompting her to respond that she received hers around the same time that he received his (as he is overweight now and has breasts). Later when she is 27 he sees a picture of her and, believing her to be his son's girlfriend, calls her hot and chesty, only to be informed that it is his daughter.