Homosexual interactions are common amongst male grey whales, where as many as up to five males will take place in an orgy. Rubbing each others bellies and genitals.
Until adulthood, the majority of juvenile, male walruses will take place in same-sex interactions. Into adulthood, generally males only mate with females during mating season, and continue their same-sex courtship throughout the year. They not only rub each other, they also embrace and sleep together in the water.
Males are normally bisexual, but at different periods will engage exclusively in same-sex interactions. Males even engage in oral sex, stimulating the other male with its snout.
Killer Whale (Orca)
Homosexual interaction happens when a male leaves his family for a male-only group. Generally only two males will participate, but groups up to four and five at one time have been observed. Males engage in reciprocal oral sex, similar to Bottlenose Dolphin, where they swim in a double helix form. Most of this behavior takes place in adolescent Orcas, but all ages have been known to take part in homosexual activities. Some even returning to a favourite partner year after year.
Male Harbour Seals are known to mount each other, causing a power struggle of aerobics, while maintaining full contact in the water. This courtship ending when the erect male, grasps the other from behind and mounting for up to three minutes. Occasionally the males make take turns.
Male sea otters have been observed mounting each other in the same fashion typical to heterosexual mating. Occasionally male sea otters will even try to mate with male Harbour Seals or Northern Elephant Seals.
Dugong (West African Manatee)
Homosexual interactions between Dugongs are generally four to eight times longer than heterosexual interactions. Males are observed thrusting and hugging, and also kissing, sometimes in groups of up to four males. These orgies, can last for hours, as males come and go, reforming and arranging subgroups.
Interestingly enough, this is not an uncommon thing. Below are seven species of marine mammals known to engage in homosexual activities: