If you come across when some Youtube videos require you to Signing with Google account to verify your Age. Youtube videos that contains explicit content that is Not Safe for age below 18 for any reason require signing in to verify user age.
So if you want to Bypass Youtube Age restriction without Signing into Google account then there is small trick that will Bypass verification process without Signing in. Reason to Bypass verification process can be many so let not discuss it and move to trick.
For Example URL of this Youtube video that require age verification because video contains scenes that is not child safe.
So to Bypass age verification process do some changes to above URL and make it look like below URL and then load video with new URL.
Exact changes need to be done to stop age verification, Remove watch? and replace = with /
This newly created URL will redirect you to new URL (https://youtube.googleapis.com/v/6LZM3_wp2ps) and start your Youtube video with resized Youtube video player that will fill whole page space.
There is also Bookmark available that you keep in your browser Bookmark bar and click on it whenever you come in similar situation. This will make your task lot easier and Handy to perform.
Just Drag and Drop below Bookmark to your Browser.
Source for Trick and Bookmark : Tired of Signing in /Signing out for youtube age Verification