Ruikuli said:
im pretty sure that ~ doesnt work in blacklist

No, but you can achieve the same effect by using multiple lines. In this case, that search would be equivalent to:

fellatio male/male
fellatio male/intersex

There's a few other things you can do that might help reduce the number of false positives, though this will always be a balancing act with the number of posts slipping through the blacklist.

For instance, here's some potential modifications / additions:

fellatio male/male -group
fellatio male/intersex -cuntboy
autofellatio