We, Large Cash, specialize in big-dick sites, straight and gay, which is not a passing niche/trend.
Mainstream or hardcore, interracial, teen, anal, Asian, fetish and cumshots aficionados all love watchin some hot babe take in a HUGE dick.
Massive Cock Videos for example offers 15-different tours with 15-free demo downlaods in various sizes/quality. It converts very well and retention averages from 2.7-3.2 months.
I have recommend to many good webmasters that they promote at the very least the one site, via recurring, along with a penis enlargement link on their gallery or wherever and many have not had to change anything as it continually converts.