Oh, this is delightful! I love this type of humorous, slightly cracky story. Snarky!Snape and "Never give up"!Harry are just my cup of tea. And I loved the way they handled the baby, the way she wormed her way right into Severus's heart, along with Harry. ♥ Awwww. (Pink heart for pink baby.) :D
... and Severus realizes, as his hips flex involuntarily, as his hands slide down to grasp Potter's hard shoulders, that he has not felt this good in some time. Upon further reflection, he realizes it's more likely that he's never felt this good in his life.
How sad to think that he's never felt that good before, but how sweet that it's Harry who's achieved this.
"You're brilliant," Potter says, his voice muffled by the collar of Severus' shirt. ... "I was wondering when you'd notice, Potter," he says tartly.
And how lovely to know that Snape will never change! :D