He could have walked in right as OP finished. OP, being afraid of someone just barging in, swiftly turns around, bada bing bada boom, brother is a toaster strudel.
I wasn't allowed to have a lock on my door for the longest time. Also OP, just leave it on the porn if you're caught jacking. It's better to be seen as a normal person who jacks to porn than a person who jacks to their mom or the news (because MSN is my homepage as well as many people I know, so if you just open a new page to cover the old it's gonna look like you were jacking to the news and that's not normal.)
This isn't Instagram. You should speak English when you use this app. Otherwise, you might need to shove a dictionary down your throat so you can actually come close to speaking a language.
Besides locking your door, install the "PanicButton". (It works on Chrome and Firefox) It closes all tabs on your computer and puts up a start up blank search page. When pressed again it restores your tabs.