It's not jizz; jizz is water-soluble. Looks more like you got some bleach on it to me, and if so, it's gonna be there forever. Look at the bright side, though: You have a new cleaning rag now.
Hard to tell from the picture, but maybe its not stained so much as bleached? Either way, hate it when that happens--ruined a jacket about a year ago after putting it down in some sort of oil while out one night. Tried soaking it and several different stain removers to no avail.
Any chance this shirt went through the wash with a pack of gum in the pocket? A very similar looking, and Levi's jacket destroying, thing happened to me once.
There's a bright side if it doesn't come out—now you've got a cool new housework/fixing the car/painting/misc dirty craft things shirt.
Try Hydrogen Peroxide, which also works really well on blood, also feel the area, if you can feel something there you may be able to peel it off, if indeed as has been suggested it's bleached, you can either use it as a work shirt, a shop rag or re-dye the shirt
To be fair to Tide, I took one of those Tide To Go Stain Erasers home last night and I used it on a shirt that got dirty on the 4th of July when I moved an old barbecue. The stain was nasty—a combination of rust and charcoal and old food. The shirt came out of the wash completely clean, and I think the Eraser must've been the reason why. So it worked for me.
I've got one of those Tide "Sharpie pen" type stain erasers, for on-the-go food stains. It's completely useless on every stain I've tried. Can't say I've tried it on [the word Bethany Jean never says] though.
Semen is viscous enough that the stain wouldn't have such sharp corners but would rather be smoother due to high surface tension keeping it from wetting to the fabric as easily.
I second the acetone suggestion, unless that shirt is made of synthetic fabric, in which case don't even think about it.
Come now. (hehehe) We all know Frizz got drunk and decided to do a little summer hair highlightin' with some Sun In. It got on the shirt and he passed out and that bleach stain is never coming out.
Looks like a paint stain - try turpentine. In Polari (Brit dictionary of gay slang), a jizz stain is referred to as "map of Africa" and that doesn't look like a map of Africa to me.
Ok, it definitely looks like bleach like other slog commenters have said, but the important reason I have added my voice here is that you mentioned that you threw it in the wash. I really hope for your sake that you didn't also throw it in the dryer. Using heat on a stain can set the stain (and then you're pretty fucked). Also I swear by tide pens in most on the go situations (my boobs are magnetic for food), but they can fuck up an item that's not colorfast/has multiple thread colors. Just FYI.
I splashed curry on a white button-down shirt. I immediately tried to clean it in the restroom. I used a Tide To Go stick and used OxyClean pre-treatment. Nothing worked. I finally found this home remedy: 1 part Dawn dishwashing liquid and 2 parts hydrogen peroxide. The stain is completely gone -- even from the buttonhole. Hydrogen peroxide bleaches, but maybe use a little bit on a toothbrush might be safe?
There's a bright side if it doesn't come out—now you've got a cool new housework/fixing the car/painting/misc dirty craft things shirt.
Also, fuck a bunch of stain sticks.
Trust me. I spilled an entire ballpoint pen into a jacket once. A bottle of acetone got that shit right out.
Anyway, yeah, that looks like a crust more than a stain, so try rubbing alcohol or acetone.
I second the acetone suggestion, unless that shirt is made of synthetic fabric, in which case don't even think about it.