Yes, you can, but that won’t let you access porn sites securely — your browser’s incognito/private mode will only get rid of some tracking cookies and clear your searches. You’ll need to also use a VPN (I recommend ExpressVPN) to encrypt your traffic so that your ISP, network administrator, or a hacker won’t see that you’re browsing porn sites. Also, a VPN changes your IP address, so that porn sites can’t log your visits and sell it to advertisers.