how can i restrict explicit web browsing

Safari doesn't have parental controls, but there are third-party browsers that do. Download one of these - MobiCIP's Safe Browser and the McGruff browser are a couple, but there are others - then turn off Safari and the ability to install apps in the Restrictions on the iPad, and set up the new browser appropriately.

As to YouTube, unless the YouTube app has content restrictions options, all you can do is remove any such app and disable installing apps in the Restrictions.

Regards.

Safari does not have parental controals. You can type your ip adress up into your adress bar and go into your router settings and disable certain websites from being viewed

Parental Controls

For setting it up on the iPod see:

Parental Control???: Apple Support Communities]

How to Setup Parental Controls on iPhone & iPod Touch | Mobicip Blogs, Discussions & Help

how do i put parental control on my...: Apple Support Communities

parental control: Apple Support Communities

time of day restriction for ipod touch: Apple Support Communities