Playfulness can ease stress and conflict in your romantic relationships. Here's how to get started.

• Playfulness among couples can lead to less conflict, trust, and long-lasting relationships.
• Playing sports, joking, and watching a comedy with your partner are all examples of playfulness.
• You should incorporate playfulness into your relationships, experts say, but start small.

Joking with your partner may be the key to a long relationship, a new study suggests.

In the study, researchers at the Martin Luther University Halle-Wittenberg in Germany reviewed existing research on playfulness among couples, then created a list of benefits, including positive emotions and easing of tension. These effects lead to satisfaction, low conflict, and sex - which can create a lasting relationship.

Playfulness comes in many forms, like playing a sport or joking and laughing with your partner. Overall, it creates a sense of lightness, according to Rachel Sussman, a relationship expert who was not involved in the study.

"Playful behaviors such as surprising the partner, retelling and reenacting joint experiences with the partner, or jointly forming new experiences often contribute to the happiness and longevity of relationships," Kay Brauer, lead study author and researcher at the Martin Luther University Halle-Wittenberg, said in a statement.

Although playfulness can lead to a long-lasting relationship, you need to have boundaries. And if you're looking to infuse some playfulness into your relationship, don't start with the kinds of shocking pranks some couples share on TikTok.

When playfulness crosses the line

Sussman said playfulness can get out of hand if someone wants to have a serious conversation, but their partner makes a joke instead.

Also, know the difference between an insult and a joke, as a hurtful comment can be disguised as teasing. "Some people's humor is cutting and that's not really humor. There's something else going on there - an aggressiveness, or even a depression," Sussman told Insider.

One example is making a joke at your partner's expense, or publicly sharing an embarrassing story that was meant to be private.

Some couples are more public than others, and some even record pranks on their partner and post them on TikTok for the world to see.

In the video above, for example, a man put hair extensions and scissors next to his sleeping girlfriend and told her she cut her hair when she woke up.

Sussman said these kinds of pranks can be playful if the couples have established that dynamic.

But if you were to perform one of these pranks out of the blue, your partner may be upset. Sussman recommends starting slow and figuring out what playfulness means to you and your partner.

Playfulness may lead to a longer relationship

Sussman said it's important for couples to incorporate playfulness into their relationship, especially for those who are bogged down by life's responsibilities.

"Everyone needs a respite from all the heaviness going on in the world," Sussman said.

For couples that aren't naturally playful, Sussman suggested watching a comedy as an easy step.

Alternatively, Sussman suggested finding an activity that brings you and your partner joy.

Watching a comedy involves more than just sharing a few laughs. Laughing leads to intimacy - whether it's sex or a serious conversation - and that closeness creates a strong relationship. What's more, people in stronger relationships tend to outlast couples who aren't as close when facing obstacles, Sussman said.