If you are using chrome or firefox as your web browser (they're better in every way than explorer) you can open an incognito window (for chrome) or private window (firefox) uder settings.
To get to these options, both browsers have the same 3 horizontal lines stacked on top of each other in the upper right hand corner, right under the X(exit button).
Also under settings (the horizontal lines you clicked) is the option to clear cookies, browsing history, etc.
For Chrome you click "History" (4th option down), clear browsing data, then check off everything you want cleared which includes cookies, simple! :)
For Firefox it's similar, you click "History", then "clear recent history", after you click that there will be an option to set the time range (I prefer to just clear everything) and there's also a "details" option with a little arrow by it, you can click that to select what in particular you want deleted.
I don't watch porn but I would assume you use some of the infamous porn sites like PornHub, I mean everyone uses it and people don't generally complain, I think I even saw an app of it on a friend's phone so famous ones like that I'm assuming are generally user friendly and well protected but idk.
Hope this helped, have fun!