hypnofck.droppages.net is a simple online tool to switch between images and create fun and hypnotizing effects. You can use it for very naughty brainwashing, but I don't think my hoster likes it when I give you examples ;)
Tip1: Use imgur.com for uploading images like your own photos.
Tip2: Use this Chrome extension to easily (re-)upload images from the web to imgur.
Tip3: Use Duckduckgo to search for x-rated pics (turn safesearch off!).
Tip4: Make sure the url you paste has an extension like .jpg .gif .mp4 or .webm!