Day time, go to your Backyard, meet Rita. Get achievement and Continue. At 6 Love Point click on her bra, she will tan without bra.
Continue. At 10 love point Rita ask you for a Tanning oil, go Market and buy it.
Back to her and use oil on her. Get achievement and continue using Suntan oil on her until she ask you for a cocktail, go prepare two, give one to her, click on the one next to you and use it on Rita tits. Lick to clean, when finish go away, she call you back to clean her pussy to. Get 2 achievement, finish.