Play the 'Pop the cherry' game and win it: Pizza girl will strip naked and her boyfriend Matt will get mad at you. Afterwards, either knock out Matt (so click the 'Counter Matt's attack' option) or lose the fight. Then go to the ferris wheel and click the "Didn't pizza girl go that way after the fight?" option. If you knocked out Matt and if you have >= 20 lockpicking skill, then you can enter and have sex with Pizza girl. Cumming after the first scene unlocks the first achievement, but clicking 'Fuck pizza girl standing up' after the cowgirl scene unlocks the second achievement, so you'll have to do this twice to unlock both achievements. If you lost the fight, you'll see Matt fuck pizza girl (again, there are two scenes for this). If you don't have enough skill points to pass the skill checks, either do the quick heist option with Red Widow during the weekend or cheat to upgrade your stats