Throughout the series, Dennis tries to bed as many women as possible to prove himself to others and sometimes to manipulate situations. His extreme vanity is one possible reason for this behavior, but regardless Dennis "bangs" more people on the show than anyone else. Dennis also keeps a camera running in his room at all times and a tape of all his encounters.
- In the first episode, Dennis has a sexual encounter with two gay men, which he does not remember due to being blackout drunk. Dee had planned to set up the encounter without Dennis’s knowledge, but did not ultimately end up arranging the event.
- Dennis unsuccessfully attempted to pick up women at an abortion rally. ("Charlie Wants an Abortion")
- An attractive high school student comes on to Dennis in the bar, but he refuses her advances due to Charlie and Mac warning about her age. Once they learn she is 18 they give him the go ahead, but she has gone back to her old boyfriend. ("Underage Drinking: A National Concern")
- In the episode "Charlie Has Cancer", Dennis sleeps with The Waitress.
- Dennis and Mac hold a competition on who can bang Rebecca Keane first. Dennis wins the competition and rubs it in Mac's face ruthlessly. ("The Gang Finds a Dead Guy")
- Dennis attempts to seduce both Mac's mom and Charlie's mom in the same episode but is refused. He breaks down and cries after these rejections. ("Mac Bangs Dennis' Mom")
- Dennis picks up a girl at a fundraiser while acting like a humanitarian with Bruce Mathis. ("Dennis and Dee Get a New Dad")
- In the season premiere, Dennis drops acid and bangs a hippie named Asriel in an elaborate plan to ruin the life of her boyfriend, Sage.
- He seduces Margaret McPoyle in Paddy's bathroom in an attempt to escape from execution. ("The Gang Gets Held Hostage")
- In "The Gang Sells Out" Dennis sets a record for getting phone numbers from what Dee calls "bar-whores".
- In "The Gang Gets Whacked" two-part episode Frank pimps out Dennis to old and ugly women. There are several encounters in this episode most notably being the mob boss' wife. ("The Gang Gets Whacked (Part 1)"), ("The Gang Gets Whacked (Part 2)")
- As his role of "The Looks" in the gangs paradigm, Dennis tries to bang a female banker. ("The Gang Solves the Gas Crisis")
- Dennis has a fixation with anonymous sex as shown in the "Mac and Charlie Die" two-part episode: after trying an orgy with Frank, he finds a European roommate. ("Mac and Charlie Die (Part 1)"), ("Mac and Charlie Die (Part 2)")
- Dennis' erotic life is chronicled in a book of memoirs, some of which are true. ("Dennis Reynolds: An Erotic Life")
- For a brief time Dennis was married to his school sweetheart, Maureen Ponderosa. ("Mac Fights Gay Marriage"), ("Dennis Gets Divorced")
- Dennis gets refused by Jackie Denardo, a large-breasted TV reporter. ("The Storm of the Century")
- After a small road accident, he meets Elena and later receives a handjob from her. ("Thunder Gun Express")
- Dennis was "forced" to bang his ex-wife, Maureen Ponderosa, by her new fake large boobs. ("The Maureen Ponderosa Wedding Massacre")
Dennis's Sexual Misconduct Edit
Dennis has an extensive history of sexual misconduct and creepy sexual behavior towards men and women. It also has been implied by the show and referenced by other characters. This includes (but is not limited to):
- Dee has accused him of molesting girls. (Charlie Got Molested)
- Everyone in the gang claims that he has always had a weird thing for younger women. (Underage Drinking: A National Concern)
- Dennis was accused of statutory rape as a camp counselor when he was a teenager ('The Gang Runs for Office')
- Dennis has said that he doesn't listen to words like 'no' 'don't' or 'stop' and that they have never worked on him before. (The Aluminum Monster vs. Fatty Magoo)
- Dennis has stuck his dick in Mac's mouth while he has sleeping, which Mac has called rape. (Mac and Dennis: Manhunters)
- Dennis threatens to have his way with the wife of the family whose home was being foreclosed upon. (The Gang Exploits the Mortgage Crisis)
- Dennis threatens to 'frame bang' the Lawyer's wife. He asks Dennis to not rape his wife while she sleeps. (Paddy's Pub: Home of the Original Kitten Mittens)
- Dennis manipulates, lies to, and threatens women using a creepy system to get women to sleep with him. (The D.E.N.N.I.S. System)
- Dennis says he used to stick his dick into his frat brothers' mouths while they were sleeping. (The Gang Reignites the Rivalry)
- Dennis says that he would like to take women onto a boat and imply that something bad would happen to them if they did not sleep with him. (The Gang Buys a Boat)
- Dee says that he rapes girls in their Y2K bunker. (The Storm of the Century)
- One of Dennis's cassette tapes reveals that he almost slept with a sixteen year old girl. (Thunder Gun Express)
- Dennis flies into a murderous rage when a woman will not sleep with him. (The High School Reunion)
- Dennis films everyone who comes into his room without their consent. (Charlie and Dee Find Love)
- Dennis claimed to enter a woman with 'almost no resistance' as he forced her head down to give him a blowjob on one of his sex tapes. (Charlie Rules the World)
- Dennis has many bench warrants for sexual misconduct. (Reynolds vs. Reynolds: The Cereal Defense)
- Dennis cannot buy a gun because he has an extensive history of felonious behavior. (Gun Fever Too: Still Hot)
- During a public breakdown, Dennis threatens to 'rate' every person in this restaurant. He also destroys many non-consensual sex tapes. (The Gang Group Dates)
- Dennis tries to enact The Implication on a boat. He steals a girl's license to ensure she is the right age and then he corners her privately and tries to threaten her into having sex with him. (The Gang Goes to Hell)
- Dennis attempts to groom a 20 year old girl into sleeping with him. (Hero or Hate Crime?)
- Frank says Dennis has seemed rage-filled and rapey lately. (The Gang Tends Bar)
The Paddy's Pub Blog released several lost chapters from Dennis' Memoirs:
- "Memoirs with a Geisha" - Dennis meets an older Japanese woman 
- "Like a Virgin" - Dennis bangs a drunk girl (which looks a lot like Dee) 
- "Knight Ride Her" - Recounts a story at a Medieval Times restaurant 
- "Cirque du So Laid" - In this story, Dennis bangs several members of a circus 
The first two chapters of the memoir were made into a bonus featurette for The Complete Season 4 DVD.