As you can tell by the disgusting humidity and mid-90s heatwave going on across the country, summer is in full swing. And, while that usually means people lathering on sunscreen and hitting up the beach, it also means that, if you’re a guy, your erect penis is officially bigger than normal. Nope, we’re not joking!

Thanks to the Internet, there’s a new phenomenon that’s been floating around called “summer penis,” which is the theory that, when aroused, guys’ dicks are bigger during the summer than during any other season of the year. Before you scoff at the idea — which was originally brought to the mainstream by journalist Tracy Moore for MEL magazine — you might want to know that doctors have officially proclaimed it to be true!

In her MEL magazine story, via PEOPLE, Moore spoke with several urologists about the idea of bigger penises in the summer. The doctors agreed that the theory was, in fact, true, attributing the bigger penis size to expanded blood vessels, unlike contracted blood vessels during colder months.

“When it’s hot outside, you may take in more water, which may, in combination with the sweating, make it appear like your body or skin is bloated,” said Dr. Jamin Brahmbhatt, a urologist with Orlando Health. “And that may give you the perception that things are larger.”

Tracy Moore’s original MEL magazine story quoted Reddit users in a 2016 forum, who claimed that their penises were bigger during the summer, also saying that they experienced better erections and had larger testicles. That got the journalist’s attention, with her adding that summer penis is just a temporary fluctuation, that, “thanks to heat and warmth, gives you a months-long leg-up on shaft size.” She related it to the possibility of a “woman’s boobs suddenly getting huge from May to August.”

The doctors who Moore spoke with seemed to agree with the temporary nature of the enlarged summer penis, even going as far as saying that it’s nothing more than an optical illusion, per PEOPLE.

But, before you go all out and start flaunting your summer penis to everyone and brag about how much bigger you are below the belt, just remember that the theory doesn’t necessarily hold true for your penis in a flaccid state. That’s according to a third urologist, Dr. Jesse Mills, director or the Men’s Clinic at UCLA, who spoke to, via PEOPLE.

While Dr. Mills agreed that there’s truth to the whole summer penis thing, he was quick to say that it shouldn’t be confused with holding true in all situations this time of year.

“Penile size in the flaccid state is purely a function of how much blood flow is circulating in the penis. The warmer the environment, the more show a man is going to have… Stick a guy in an ice cold lake in the middle of the summer and his penis will shrink to winter size,” Mills said.

So, yep, summer penis is 100 percent a thing — but only when you’ve got an erection. Knowing what we do about the theory, just be proud of yourselves for looking a little bit bigger down there when you’re aroused, but don’t be bragging about it, ’cause it’s not going to look that way in a few short months.