overlapper 

One who fails to break up in a current relationship before starting a new one.

or if you are from Massachusetts... ova-lappa

"Fran is an overlapper. Afraid to have the awkward breakup talk after they have found another lover."

overlapper by HBombD June 30, 2017

Overlapper 

Someone who is always in a relationship. They can't stand being alone so they have the next person lined up before breaking up with their current fling.

Dang! Jason just broke up with Lilly a minute ago and is already out with his new girlfriend, Amy. Oh you KNOW he's an overlapper!

Overlapper by TypeJ January 15, 2016

overlapper 

A person who isn't "quite done" with one relationship before they start up another. This person does not refer to themselves as a cheater because "they were getting around to the breaking up part." They also don't consider themselves codependent, even though they can't stand the thought of being single for one bloody minute. Technically, however, they are both.

I'm not that picky about the women I date; I don't care if they're divorced, or if they have kids, or if they have a bunch of kids, like more than two. I just don't do liars, cheaters, or overlappers.

overlapper by Banter2012 December 28, 2015

Salami Overlapping 

An Act of homosexual intercourse. It involving to males in which they both retreat their foreskin and press their glans together. Then, the first male rolls up his foreskin on both of their glands. Finally, the second male rolls his foreskin over the other males one.

We couldn't separate our dicks after the salami overlap
or
My cock and bolex ripped open when I fell backwards while salami overlapping!

Salami Overlapping by peppolla October 14, 2009

overlapping snacking 

when you treat yourself to a snack while preparing another

I was making a toastie so i thought I'd do some overlapping snacking so i went and treated myself to a mars bar while the toaster did it's thang

overlapping snacking by Hopsticks July 22, 2010

overlapping 

Typically performed by someone who is not loyal. They will constantly move around looking for the 'next best thing'.

If you date an overlapper, you need to constant look over your shoulder. It doesn't matter how much you tell them that you love them, they will immediately and without warning start dating someone else. If they are a coward, they will break up with you and give you a completely different reason for the break up (e.g. they will lie and not admit they are breaking up because they found someone else). If they are particularly selfish, they will deny you had a relationship at all.

Steve: So I was just a victim of overlapping!
Joe: She did the same thing to me, why are you surprised? Every relationship of hers ends with overlapping.

Steve: But, I thought I was special.
Joe: Yeah, she makes everyone feel that way, until she flushes you down the toilet, and moves onto the next best thing.

overlapping by ChodeYourself March 31, 2016

overlapping 

NOT cheating, technically. When you start dating someone new before you've actually splitsville with your old significant other.

I'm overlapping with Terry because we hooked up and I haven't dropped Jenna yet.

overlapping by IzzyMargoStevens February 20, 2006