Is there a class of dildos or plugs designed specifically to keep semen from leaking out?

If so, what are they called? Are there any safe versions or are they all unsafe?

What practical concerns or limitations on their use exist, beyond the obvious of menstruation and defecation?

Is a shape possible that instead of funneling semen towards the opening of the orifice, funnels it deeper inside? One that is also generally comfortable for the party it would be inside?

If there's no dedicated class of dildo or plug for this kind of purpose, are there others that suit this well, or is it basically a matter of throwing various types at the wall and seeing what sticks?

Or more just impossible/a really bad idea to do, due to semen decomposition or toxic shock or something?