Still, the OP question remains, can i attack myself with the whip and benefit from the spell as well?
...and voluntarily drop my AC to accept the attack? would i trip myself? 
OH! Why didn't you say so?
At 13th level, you can cast any touch spell you know as part of a full attack action, and the spell affects each target you hit in melee combat that round.
When you use the full attack action, you can give up your regular attacks and instead make one melee attack at your full base attack bonus against each opponent within reach.
See the bold words? One say target, one says opponent. Now, target is any valid target, as defined elsewhere, but in this case, we can assume it means anyone you could cast the spell on. for example, you could not target, say, a tree, unless said tree was a valid target for the spell itself. The target line of your spell you are choosing to use would determine that.
Now, Whirlwind attack says opponent. Now, unless you hate yourself and have self-esteem issues, you would not fall under opponent. So, you cannot whirlwind attack yourself. (This is to provide a negative example)
So, to answer your question, yes, assuming you are a valid target for the spell.
As for dropping your AC, you can, but the problem is, You can only lower it once and it applies to everyone. You simply choose to become flat-footed, effectively. But once you drop it, you can't be selective about it.
Now, that said, I haven't searched every book in existence, so perhaps I'm missing something somewhere that specifically states you can do this. I've been filling my head with weapon stats and it tends to push out other info.
