The “monsterworm” on the left is by Jethro Bijlaart at Mounty Zoo Tattoo in Bergen op Zoom, the Netherlands. The other two (the lock and the pubic Taz) are the work of Al Farber at Acid Works Tattoos in Mount Morris, MI.
I’m not so sure that I find the specifics of any of them a big turn on for me personally (I’m 99% sure I’ve never jerked off to either Tremors or Taz cartoons), but I assume they are for the wearers and/or their partners. People (men and women both) get some funny things tattooed on and around their genitals (check out the galleries in BME/extreme if you’d like more).