Incesteresting 

The act of watching family members engage in sexual activity and finding it arousing.

The video of these two lesbian twins eating eachother out is incesteresting.

Incesteresting by Jarrett December 1, 2004

intensteresting 

when something is both intense and interesting but not quite more of one nor the other

wow that that movie was intensteresting or when the man spoke i was intensterested

intensteresting by kicketty April 10, 2008