Most, of not all will use something to get them looking best. For example, pumps have been used for many years, and still are across all genres, and races in adult entertainment because they work at getting the penis erect, larger with speed.
Viagra and alternatives are used for maximum EQ.
Some have used natural penis enlargement, as Lightning & DLD both know from meeting stars at bangbros who used MOS products to enlarge themselves.
Some will have gone under the knife .. I think the English guy called Jez Christ did so, but thats just my own opinion.