S to the i to the m to the p
means SIMP; from Phineas and Ferb, it would mean Squirrels In My Pants (a meme that felix will never understand because he's a simp)
Candace: AHHH SQUIRRELS IN MY PANTS!!!
Phineas and Ferb at the same time: S to the I to the M to the P
Phineas and Ferb at the same time: S to the I to the M to the P