The chord that is made purely of the notes C#, G and another C# is used frequently 
throughout this song.
I can't find a name for it, but it is close to Dbb5, which also contains an F.
The chord is denoted as Dbb5 but can be played like this without the F.
e------|
b------|
g-6----|
d-5----|
a-4----|
e------|



Gm (355333@1)                Dbb5
 I was thinking of sex and

Gm (355333@1)            Eb (x43121@3)name="chord_xx0212@1">D7
All the nasty things we do

Gm (355333@1)                Dbb5
 I was thinking of love and

Gm (355333@1)        Dbb5
How you got none in you

Gm (355333@1)        Dbb5       Gm (355333@1)        Eb (x43121@3)D7 (xx0212@1)I piss my pants in an expensive suite

Gm (355333@1)          Dbb5            Gm (355333@1)        Dbb5
 I can keep my hat on in the worstest hurricane (make it rain)

(Pre-Chorus)

Gm (355333@1)            BbHold (x1333x@1)me, I get lonely

Cm (x3101x@1)        DI (xx0232@1)can only wait so long

D7 (xx0212@1)       GmI'm (355333@1)losing my mind,

Bb (x1333x@1)          D7Losing (xx0212@1)my mind

(CHORUS)

GmKeep (355333@1)the flowers

Bb (x1333x@1)                GmI'll (355333@1)just give 'em back

Eb (x43121@3)          Bb (x1333x@1)              D7'Cause (xx0212@1)the only way to my heart is with an axe

GmKeep (355333@1)the flowers

Bb (x1333x@1)                GmI'll (355333@1)just give 'em back

Eb (x43121@3)          Bb (x1333x@1)              D7'Cause (xx0212@1)the only way to my heart is with an axe

(Gm,Dbb5,Gm,Eb,D7, Gm,Dbb5,Gm,Dbb5)

Gm (355333@1)      Dbb5           Gm (355333@1)A cup of coffee before bed

Eb  D7
So I dream fast

Gm (355333@1)           Dbb5
 I stoled your car that

Gm (355333@1)       Dbb5
I purposely crashed

(Pre-Chorus)

(CHORUS)

EbLet (x43121@3)me let you know
GmLet (355333@1)me let you know
D7Let (xx0212@1)me let you know
EbYeah (x43121@3)yeah yeah yeah

GmLet (355333@1)me let you know
D7Let (xx0212@1)me let you know
EbLet (x43121@3)me let you know
GmYeah (355333@1)yeah yeah yeah

D7Let (xx0212@1)me let you know
EbLet (x43121@3)me let you know
GmLet (355333@1)me let you know
D7Let (xx0212@1)me let you know
EbLet (x43121@3)me let you know
Gm,D7,Eb

(Pre-chorus)
(Chorus)

Use verse progression for first set of 'let me let you know's following final chorus:
(Gm,Dbb5,Gm,Eb,D7, Gm,Dbb5,Gm,Dbb5)

End with alternating between Gm and Dbb5.