Yes and no. A dolphin's penis, when erect, is shaped vaguely like a hook, so when males copulate with females, the chance of them being accidentally separated is eliminated. Think of the penis as a key, and the female's vagina is a lock. It's meant for securing, not necessarily grabbing.
Penises.
Yes, dolphins have penises. Only male dolphins, though.
Their penises are too big
It is said to be prehensile.
Iguanas do not have a prehensile tail.
Prehensile means they have control over it, a spider monkey has a prehensile tail and can use it to cling to branches and things. Prehensile appendages are usually used like we would use our fingers.
Baboons and Mandrills do not have prehensile tails. They are large monkeys that spend most of their time on the ground. For that reason, it is not necessary for them to have a prehensile tail.
jjk
Giraffes
Some species of Australian possums have a moderately prehensile tail.
becasue
Yes I imagine that all mammals have penis, but I didn't see the penis of a whale yet. So I don't know what its shape looks like. Moreover I am not a specialist on penises, I care only with my own.