Is your site structured so it would be useful for brands to have profiles on there and fit the vibe of the site? If there is a way to flow eyeballs more naturally that way, it could be an option.
Some of it depends on what your users want. Do they want to buy site memberships or buy private cam shows or find new partners or find opportunities to show off their sexy selves? For a legit UGC site, a program like
Chaturbate where they will pay you $50 for new cam broadcasters on their site could be a great fit for you. You already have a userbase who presumably likes to do exhibitionist activities.
Basically, to not irritate people with advertising, the most important thing is to think about what adverts give additional value for your users and which would just use up real estate on your site where they would rather see something else.
Good luck!