Is it ever acceptable for Christians to watch explicit videos?

My opinion: yes, but only with respect to genuinely educational videos

- e.g. videos that help a woman to prepare for pregnancy, sex-ed videos for young Christians, etc.

or perhaps also to personal ("home movie") videos (but I am not concerned since I am not so inclined - why watch what you once did when you can do?)

You should probably keep your nose out of friend's bedroom before you lose a friend.

That is disgusting, to watch someone have sex.

Is it acceptable to have Sexual educational courses according to Proverbs 30:18-19 with Smokey the Bear has mascot? <Can More Than a Khanqueror Uncle Travus One Man Army Kuiper Juan Amongst a Trillion DuMore Good by Any and All Mighty Means Necessary in The Almighty Name of The LORD YaHaVaH Who Was Is and Will Be The Only True God and None Other Than our Great God The Righteous Tsalvation of Justice Anointed King of kings Lord of lords God of gods The Tsupreme Jesus Christ Tzedekelizedek HaMashiach a High Priest Forever and Ever and Evermore According to the order of Melchizedek get an Amen Hallelujah and i Believe?>

Sounds like he's using mental gymnastics to justify something he thinks is wrong.

not really but adult content is also off limits

simply put, if the "porn" is creating lust in him, then he is wrong...

Your friend is committing the common practice of attempting to justify our personal sins. "Yes, it is sinful for everyone else, but not for me, because ...."

It's not your choice to make.