How can you watch porn securely, privately, & safely on your own laptop?

Start by subscribing, downloading, and installing a VPN client. Don’t grab the cheapest one, but rather you want to find a VPN that protects its users. Many VPNs are not as secure as users are led to believe. You want a VPN that will NOT provide your browsing history to anyone, including law enforcement. This typically means investing in a VPN based overseas. Ultimately know that at absolute best, you will leave a trail on your computer as well as to the server you’re connecting to. There’s no way around this.

Next up, if you’re using Internet Explorer, get rid of it. Use either Chrome or Firefox or other similar third-party browsers. Install an ad-blocking add-on to the browser. If you want to go the extra mile, also incorporate a flash-blocking add-on as well. Next, go into the settings and disable any auto-forwarding and auto-refreshing. You want full control of your browser. If a page wants to refresh, you want it to ask permission before doing so.

Following that, install an anti-malware and anti-spyware client. The goal is always to avoid malware and spyware, but sometimes things happen. So have then programs installed to protect yourself in the event you’re exposed to any other these. Malwarebytes and Super Anti-Spyware are my two favorite free clients that work quite well.

Now it’s time to get to the porn! First, turn on and connect your VPN. Do a few IP address checks to ensure your public IP is different from what it originally was. 
Using one of the browsers you’ve installed in lieu of IE, open their private browsing option. The verbiage may vary from one browser to the next. Once opened, access the porn site of your interest. I highly advise you go to well known, well established, and pay sites. These sites have paying members, which means the sites are going to do their absolute damnedest to ensure their users (you) don’t get infected by malicious software. Free and tube sites tend not to care as much. So where possible, opt for paid subscriptions. Don’t worry, when they appear on your credit card statements they’re usually quite discrete.

Once you’re done, close out of your private browsing windows, close your VPN, If you’ve downloaded anything, delete the media as well as any temp files you’re accumulated in the process. 
In the event, you happened to collect cookies while browsing, run your anti-spyware software. Most of these programs will find and delete tracking cookies. Again, know that your computer still will have traces, but they’ll be fairly deep to the point where you’d need a decent amount of computer knowledge to recover them. 
By default, private browsing will not store your browsing history, websites, and logins, so those should be nonexistent automatically, but it’s still good practice to double check.

That’s more or less it. Again, know that if you have a friend or parent that knows a lot about computers they may be able to dig up a few cookies and evidence to find out what you’ve been doing. The other side of this is that with all the hiding, the void you’ve created may raise alert to your activity as well. So keep that in mind also.