I was with my friend. We were having a friendly online game.
He sent me a link and it depicted ponies with genitalia showing. I got a flat out erection. I couldn't help it. I quickly exited out and came straight here.
Help! What's happening?
The wicked get their jollies connecting images of innocent childhood with sexual ideas. It is the shock of the connection that gets people's blood pressure to rise and to get stressed, thus making it more likely to have an erection. Since it involves a sexual theme then it makes it even more probable.
Paul warned: "But fornication and all uncleanness or covetousness, let it not even be named among you, as is fitting for saints; neither filthiness, nor foolish talking, nor coarse jesting, which are not fitting, but rather giving of thanks. For this you know, that no fornicator, unclean person, nor covetous man, who is an idolater, has any inheritance in the kingdom of Christ and God. Let no one deceive you with empty words, for because of these things the wrath of God comes upon the sons of disobedience. Therefore do not be partakers with them" (Ephesians 5:3-7).
These types of things aren't funny. They are aimed at corrupting the mind. Everything is seen with a sexual theme. It is far too easy to lock in habits, especially when sex or sexual arousal is involved, and you don't want sexualize children or things connected with children.
Make it clear to this boy that you don't ever want to see such a thing again from him or he will need to find a new friend.