They could throw them in the air, and wave 'em like they just don’t care.
Couldn’t hit the curve, either.
Ray Bradbury suggests that they may have been capable of building quality timepieces.
From “A Sound of Thunder”: “It towered thirty feet above half of the trees, a great
evil god, folding its delicate watchmaker’s claws close to its oily reptilian chest.” Sadly, they didn’t have access to the types of tools required.
Here’s what Wikipedia has about their arms:
Clearly, there’s some debate about it. Since their forearms were probably fairly strong, I think the odds are against them being purely vestigial.
I guess we will never know… until the new Jurassic Park movie comes out 
Arms that small would be useless for reaching their own junk, so self-pleasuring was clearly right out.
Well, once their snout got long enough their arms fell into disuse.
Serious question, what about juveniles? Was their arm to body ratio different? I wonder if they out grew certain behaviours the way that Komodo dragons get too big to climb.
Ok, that was a throw away comment, but know I’ve got an image of a T Rex cleaning his junk like my last dog, it’s rather disquieting.
What kind of junk did dinosaurs have? A male lizard’s can be . . . interesting.
Funnily enough, the exact nature of T. rex genitals is not actually known.
However, given that their closest living relatives are birds (which are also theropods, though not in the same branch thereof as Tyrannosaurus), they can be theorized upon. They will, obviously, have had cloacae, just like birds (and crocodiles, and other, more distantly related, reptiles). Given the rarity of phalli among birds, they can be surmised (though not proven) not to exist in T. rex, who would then have reproduced via a cloacal kiss, like most birds.
Well that’s disappointing.
Good point.
Well that’s even more disappointing. I was kind of hoping they’d be more like ducks.
Band name!
Yes, but as a consequence their vision was razor sharp, so they had that going for them.
Ya know, I’m gonna go out on a limb, and speculate that we don’t know shit about T Rex vision, either.
[Alan Grant] Don’t move! He can’t see us if we don’t move! [/AG]
Last I checked there have been no soft tissue impressions of dino genitalia.
It’s a mystery how some dinosaurs mated, such as stegosaurs or ankylosaurs where both sexes are highly armored and covered in spikes. Or the larger sauropods, which presents all sorts of logistical challenges. The consensus seems to be they either used highly creative positions that wouldn’t be out of place in the Kama Sutra, or it’s possible the males had a long prehensile penis to bridge the gap (like the aforementioned duck penis).
Many years ago, I was at a zoo wherein a male elephant had an erection. Men were running away, women were fainting and little children were furiously tugging at their mother’s skirts (to get her attention).
That thing was alive! It was whipping all around like it was blind (well, you know) and every so often peristaltic waves would shimmy up and down its length as though it didn’t know whether it was coming or going (well, you know).
Since then, I have learned about the circuitous path it must take inside the lady elephant’s hoo-hoo and can better understand the design parameters. This sentence in the Wiki did rather leap out at me, though.
I can only hope “independently” doesn’t actually mean “independently.”
It is self-thrusting, not relying pelvic thrusts to move around. It is still attached at the one end.
The female elephant’s birth canal travels from the normal mammal vaginal exit down the torso and out near the belly button. This is so a baby elephant doesn’t have as far to fall when it comes out head first. The male elephant has to get his penis up this extra long channel that bends backwards, do it blind (he can’t see the opening), can’t guide it with his hands or get an assist from the female, and can’t pelvic thrust as the load is too great to go throwing around like that. The penis has to do a lot of stuff for itself.