Cohabitating leopard geckos is not recommended with the current knowledge we have of their husbandry and behavior.
In the wild, leopard geckos typically live alone within larger groups. As in, a group of leos will all live in one area, but each individual will hunt their own food, sleep in their own area, and find their own resources. These groups are typically all female or all female with a singular male. It is also important to note that for the most part, these geckos will not be interacting with each other and only do so in passing or for mating.
When cohabitating in captivity, leopard geckos tend to fight over resources. They are very territorial and will fight to the death if they feel threatened, stressed, or just don't want the other present in their territory. These fights may not always be physical or visible if you don't know what to look for. Fighting can also present as one gecko resource guarding until the other dies of malnutrition or mbd.
Cuddling is a behavior commonly overlooked by those uneducated on leopard gecko behavior. It's even seen as cute and loving by many people. However, it's a form of resource guarding and a display of dominance. One gecko may lay on top of or blocking the other. This is done to steal the other's light, warmth, and prevent it from accessing other resources. Unlike humans, leopard geckos are unable to feel love or any other similar emotions. While they do have basic emotions such as annoyance or happiness, they can't feel complex emotions like love. Many people think cuddling geckos just love each other and don't want to be apart, but that is not the case.
Another problem to look out for when cohabitating is keeping a male and female together. If kept together, the male will end up killing the female by mating to death. Females tend to only want to mate once when they are ovulating. Sometimes they will mate more than once if their eggs were not properly fertilized the first time. Males on the other hand will just continue going whether the female wants to or not. She may try to fight him or run away, but he will still find a way back to her. Mating to death can take months or even years, but ultimately the female will become extremely malnourished and exhausted. Over the course of years, she'll lay more eggs than her body can handle, and it will leave her extremely weak. If she has another clutch after that, the likelihood of her dying is extremely high. While extensive mating is typically a risk for a female, it can also be a risk for the male. If he is inserted and the female tries to fight back or run away, his genitals can be ripped. He can also get bad infections or have his hemipene get stuck outside his body rather than inside.
Here are some photos taken as the result of cohabitation.
Is there a way to safely cohab leopard geckos?
Overall, the answer is no. Even geckos who have lived alongside each other for years have been known to randomly snap and end up harming and sometimes even killing the other. Many people still believe that experienced keepers can cohab safely, but the reality is that leopard geckos are animals, and animals can be unpredictable. Even if you take precautions such as keeping them in double the minimum space, providing tons of hides, having multiple water bowls, etc. you still have the chance of coming home one day to only one living gecko.