Gay bashing is random as to the individual selected, who may not even be gay but just appear to be to the assaulters, but it is not random and tends to have some distinct attributes of a sexual nature.
I'm going to assume a group of about three to four guys, fueled by some level of alcohol consumption. Most likely to happen between midnight and three AM. I'm also going to assume that it is unplanned, and the victim is randomly chosen as the assaulters stumble around after leaving a bar.
It will start out with the assaulters surrounding the victim, and taunting him. This is needed to both boost the assaulters anger and also for them to assess the victim's response. Remember the assaulters want to beat the snot out of someone, not get hurt themselves. This is when they find out what the potential for them being hurt is. This stage will last a minute or two. Victim response of trying to avoid trouble is what the assaulters are looking for.
Then the assaulters will start a game of pushing and bouncing. The idea is to push the victim into someone else, who pushes the victim into someone else and so on and so forth. This stage will last about thirty seconds to a minute before someone decides to bring this to the next level.
The next stage usually happens by someone bringing up a knee as the victim is bounced towards them, connecting the knee with the victim's groin. Massive and immediate pain. Victim will immediately collapse to the ground, curled up in the fetal position. Ruptured testes and injured bladder, especially if the bladder is full, are possible. Testicular torsion is also possible. Inability to father children can be a direct consequence. Surgery may be needed. At best, ice packs and more ice packs are in someone's future, and swelling may take a week or more to go down.
Victim is now on the ground, curled into a fetal position. This position is done both in response to the pain, and also for protection. Hands and arms will be supporting and protecting the head. Victim is now in survival mode.
Kicking commences, and it really depends upon the deliberateness of the kickers and the type of shoes they are wearing as to the injuries. At a minimum, massive bruising of the scalp, back, butt, arms, and lower legs. Possible injuries include skull fractures, spine injuries, broken arms and legs, and dislocated knees, elbows, and ankles.
More deliberate attacks will include stomping on the rib cage, as the victim lies on his side, causing broken ribs. If you're a thorough going bastard, you can easily break every rib on one side. Chance of lung puncture in that case is high.
This stage will last about a minute before the attackers energy is gone. At this point, the attackers might leave, or they might gild the lily. Additional attacks can consist of urinating on the victim, defecating on the victim, inserting something into the victim's anus, writing names on the victim, and picture taking. This stage can last about five to ten minutes.
With what you want for injuries, I'd go with massive bruising, broken lower arms (ulna and radius bones), lower leg (tibia and fibula bonds also known as a "tib-fib" fracture), ruptured testes, torn anus, and dislocated knees. For about 48 hours, patient will probably be touch and go from shock and hypothermia. Patient will probably be unconscious during this period.
After that, the patient has several major problems. Going to the bathroom, either way, is going to hurt. Dual breaks in his arms means he's not going to be able to do anything without physical assistance. Legs are going to mean a wheelchair and learning how to walk again.
Because of the fetal position he's most likely to assume, internal injuries will be minimized.
ETA -- Attackers are wearing construction type boots with steel toes. Attackers are blue collar workers.
Best of luck,
Jim Clark-Dawe