Taddlee Men Swimwear Swimsuits Flower Print Surf Board Boxer Shorts Trunks Long (L,S209)

What are these made out of? Spandex?

Large is a bit too loose around thighs and front area, but Medium seems to fit just right, but slightly tight. Do these shrink in the hot tub?

Is the waistband elastic on these shorts?

How tight are they ?