There's a Hardy Boy in my pants, if you know what I mean.

Base +6, xburner337 +6, Seelenmord -10, PokeTFFan +5, sir_gamer +6

Jeez, how long did the other girl watch before finally intervening.

Base +6, berning4u +4, xburner337 +6, xXGottSteinXx +6, blagblag +7, Encuilion +7, Novanity +5, PornFilter +1, sir_gamer +6, idfkidfc +5, Finnish_Nationalist +6, poisonace_ +1

Tentacruel in a lake? Really?

Base +16, akimiimaru +6, berning4u +4, KarlRyu +6, xburner337 +6, xXGottSteinXx +6, DekomoriDesu +14, linksbro1 +8, Novanity +5, HamburgerHelper +7, PornFilter +1, sir_gamer +6, 1qazqaz +6, and 2 more...

I mean, Tentacruel is a Poison-type, Super Effective against Lilligant's Grass-type, so I was kind of expecting a double rape, but more focus on Gardevoir is great too.

Base +4, Novanity +5, sir_gamer +6, splat68 +4, Hyoros +14

Tentacruel is weak to Psychic, Electric, and Ground, but since they have decent special defense, a physical Ground-type move like Earthquake should get the job done.

Base +7, Arkannum +9, sir_gamer +6, PC-Reviver -11

@ NiGHTS4life
While that is true, neither Gardevoir nor Lilligant can learn Earthquake, and they have low Physical Attack, so that solution is not really relevant to the situation at hand.
Psyshock, a Psychic-type Special Attack that deals damage based on the target's Defense stat, can be learned by Gardevoir, and is the most useful move available to them for this situation.

Base +4, E Pluribus Eunuch +2, Newtypeswag +6, PC-Reviver +11, jojosbrion +6, MacrossSkullOne -6, kiwino +14

I would more like to see a female tentacruel attack to male's

Base +7, splat68 +4, freakyshotafreak +6