As the unlikely duo walk across the beach, they'd see Pokey walking up from the water. The Slowpoke has a raging erection between it's legs, it's obviously looking for a fuck. Being slightly psychic, but not a master of controlling it like the Alakazam most certainly is, he gives off a slight psychic pulse as he approaches the pair.  It isn't intentional, and It's unnoticeable to those without psychic abilities, but it's just his urgency to fuck transmitted through psychic waves. To those who aren't dark types or strong psychic types, it would subconsciously make them slightly aroused even if they couldn't consciously detect it. It wouldn't necessarily make the creature want to fuck him however; in the case of Gex it's likely to make him think of naught thoughts of Alice if it even effects him at all.