Positive messages in That's My Boy are mostly aimed at adults to be better parents and not completely damage their children's emotional lives. There's also a lesson about truly knowing the person you're going to marry. On the downside, much of the movie's humor is at others' expense and/or gleaned by mocking particular groups (the obese, etc.).
Mostly comic violence. Donny and Todd get in a few fist-fights, which they usually resolve by hitting their opponent with a bottle to the back of the head. Donny, Todd, and Vanilla Ice anger several different crowds of people who chase them from place to place -- including a convenience store, where the owner is trigger happy and shoots off his gun (again and again). Even a priest punches a couple of people.
Like most of Sandler's lowbrow comedies, That's My Boy has tons of references to sex and several scenes of nudity. Incest, masturbation, erections, penis size (even that of a young boy), semen, oral sex, happy endings -- all are heavily explored in the dialogue. Frequent sex scenes feature everything from an adult teacher and her 13-year-old student to a long sequence about a man masturbating to a photo of an elderly woman to a shot of a brother and sister having sex. Donny's home away from home is a nudie bar where the strippers are topless or wearing just pasties and a thong. Sandler often goes for laughs at the expense of very large people, so there are several shots of naked obese people either as strippers or in other situations. Women are frequently treated as objects.
Barely a sentence of dialogue is free of swearing, usually "f--k" and its many derivatives, including "motherf---er" and "brotherf---er." Other words are also used liberally, including "s--t," "a--hole," "ass," "bitch," "hell," "crap," "damn," "goddamn," "oh my God," "whore," "d--k," "p---y," and many other slang terms for genitals. There are demeaning words and culturally insensitive jokes, as when a woman says "Chinaman," and the East Asian butler and maid are used for laughs. A black priest says "White people are f---ing crazy."
Many product placements -- mostly beer companies (Rolling Rock, Budweiser, Miller Light, Sam Adams, Busch) and cars (Fiero, Mustang, Cadillac). Also references to/appearances by Groupon, Angry Birds, Axe body spray, Vaseline, Taco Bell, Vaseline, and Newsweek.
Drinking, Drugs & Smoking
Donny literally has a beer in his hand for the majority of the movie. It's a running joke that he drinks beer first thing in the morning, all throughout the day, and even in the shower. He pulls them out of pockets, drawers, and other unexpected places. During the bachelor party, the guys get so drunk they can't even stand. Marijuana is consumed, and a man has white powder on his nose that's obviously supposed to be cocaine. Donny mentions that a bachelor party should have a ton of blow, strippers, and hookers to be fun.