The erection won't do you much good as you try to avoid going into respiratory arrest:

Symptoms may appear within 10 to 20 minutes after the bite, and death within two to six hours, where severe pain radiates to the rest of the limb, systemic effects include tachycardia, increased blood pressure, vertigo, fever, sweating, visual disturbances, nausea, vomiting, difficulty breathing and paralysis.

Alternative wording is gives you an erection for the rest of your life.

So, uh, is the spider hotter in person? Because the picture isn't doing it for me.

FWIW, even if it only caused a four hour long erection, that is not what your partner is going to want.

Trust me on this.

After an hour--usually less than half an hour, IME--it's not going to matter how much lube you have, they're going to be hurting. You'll be frustrated, they'll be frustrated and in pain, and no one is going to be happy. Maybe there are a very, very few women that like getting pounded for over an hour straight, but I haven't dated one yet.

and then you die.

Priapism isnt something you want. Eventually the blood will clot in your penis and no new blood can flow in, causing the cells in your penis to die from lack of oxygenated blood eventually leading to amputation. Better make those 4 hours count

Doesn't it lead to erectile dysfunction for several months after being bitten? I mean on top of the pain and non usable erection? I guess I don't want to try, thanks.

That's a challenging wank

You don't want that spider bite: https://youtu.be/JN0VtHez9xI (12:35 SmarterEveryDay video)