"You should wear heels. Maybe you'll be as tall as everyone else then." - Danny to Sam
Dam is the amazingly titled friendship/romantic ship between Danny Vespa and Sam Riddleman. Danny had already obviously heard of Sam before meeting her, and must have been a fan of her because he continued talking to her after they met in a music store. They quickly became friends, mainly aided by the fact that at the time, Sam had a boyfriend. Sam and Danny hung out again for Danny's birthday and got drunk and acted all sexual, but the whole time Sam was basically offering to be a wingman for Danny. Unfortunately the media didn't think it was all friendly and playful and started spreading reports that Sam was cheating on her boyfriend with a mystery man.
After her boyfriend started being a jerk, Sam went to Danny for comfort, thus totally disproving her boyfriend's point about how she was flirting with Danny. Sam and her boyfriend broke up after he accused her of flirting with Danny and although Sam's initial instinct was to go out clubbing, she instead spent the night with her roommate, Kieran, who suggested that if she wanted to find a lasting relationship she should maybe date someone she didn't meet in a bar (remember that time that I said they met in a music store?). Anyway, stuff happened and Sam slowly realised that Danny had a crush on her (he didn't really hide it anyway) and eventually decided that the best way to make his crush on her go away was to make out with and then later have sex with him.
They had a weird relationship for a while where they were just friends with benefits, and even though people around them noticed (e.g. Kieran), they still denied it. It wasn't until they went out to some club and got into a bar fight that Sam and Danny officially declared their thing a relationship.
That being said, their main dynamic consists of the two of them being lazy bums who like music and joke about stuff and how great they both are. Danny also makes fun of Sam's height a lot, seeing as he's 6'2" compared to her 5'4" even though he probably shouldn't, because Sam can be a fiery ball of anger when she wants to be. They both don't do a lot of stuff in their free time other than each other, and now that they're dating, they do even more of nothing.
So after Sam argues with her boyfriend a bunch in other friends about accusations of cheating, Sam decides to introduce Jaime to Danny and Jaime accuses her of flirting with Danny again. Sam's like nah I ain't flirting and goes to Danny for comfort because her boyfriend is a jerk.
Sam calls up Danny and invites him out to some music store which is having a closing down sale and then after some conversation and butt grabbing, Sam gets Danny to describe his perfect woman so that she can set him up on a date with her.
Danny comes over to bother Sam and she's like let's get out of here because my brother and roommate think we're dating and so they go for a little drive before Sam's like "pull over" and he's like "sure why" and they end up having sex in his car before going to a restaurant and continuing to joke about having sex with each other.