Natural and Manufactured Weapons (3.5)

[Chronos Flame]

So I am wondering exactly how this works. I don't have all of these attacks yet but I am going to post what my (non optimized) character will have in terms of attacks at 20th level. So the breakdown will look like this...
15BAB
Greatsword
4 Tentacles
1 Bite
4 More tentacles (different source if that matters)

So correct me if I am wrong but... Assuming GS as primary then:
GS+15, GS+10, GS+5, Tentacle +10(x4), Bite +5, Tentacle +0(x4).
Is that even close? If not what order should I use my attacks in order to get the most out of it?

[deuxhero]

I assumeing 3.5 (you should note system in a title, unless it's as-system like a player/GM issue).

Natural weapons don't get additional attacks and only care about BAB for to-hit and damage, when used with a manufactured weapon, they are all considered secondary (at a single secondary penalty, unless you use an ability that explicitly applies to all attacks, like flurry of misses blows) and you get all natural attacks along with your irritives on a full attack.

[Chronos Flame]

So then they all take the simple -5? So My first greatsword attack is +15 and all my natural attacks are at +10?

[Dusk Eclipse]

So then they all take the simple -5? So My first greatsword attack is +15 and all my natural attacks are at +10?
AFAIK yes, but I think you should get Multiattack (MM & SRD) to reduce that -5 to a -2

Edit: BTW what is your build? I guess it is a Psy war 20 with bite of the wolf and form of doom manifested.

[Chronos Flame]

Yes, it is Soulbound Greatsword, Bite of the wolf, Form of doom, and Illithid grapple 4 times. It's only level 5 right now but it's proving to be a very fun build to play so far. I am planning on no multiattack for a while because the build requires a lot of feats the way I have it right now...