Most of the videos on youtube have Unrated or Adult tag due to security reasons. So if you want to watch these than youtube will ask you to sign in before watching these and this is very annoying. Everytime you have to confirm you birth date. But i am going to tell you how can you watch 18+ videos without signing in to youtube.
Follow the steps below to watch 18+ youtube videos without Logging In:
Step 1. First of all get the url of the video you want to watch. This might be like
Step 2. Now copy the video id that is 4Xkh6j7RMqk for the above link
Step 3. Now paste the video id in the link given below.
Replace the video id you copied in step 2 with the VideoId in above link.
Step 4. Now you will get a new url that will look like
Step.5. Enjoy. Youtube will not ask you for logging in after this.