One of the most oft-requested feature in Sims 3 was the slow dance, and with The Sims 3: Seasons, developer Electronic Arts has granted that wish. This is a special type of dance reserved for couples and can't be performed alone; while your partner doesn't need any dancing skill, your Sim must have reached at least level 1 in the hidden dancing skill. This is the only dance your Sims can perform without any music already playing in the background.
Developing the Hidden Dancing Skill
As dancing is a hidden skill, there is no way to visibly track your progress without performing the skill. Toddlers learning to walk and talk are a good example of hidden skills; you can see the skill bar above the Sim's head while practicing, but you won't see progress otherwise.
Turn on any stereo at home or on a commercial lot; click the stereo and select "Dance." Pressing "3" on the keyboard will advance the time more quickly so your Sim gains the dancing skill in a shorter period of time. When he first gains the dancing skill, you'll receive a notification, leaving no guesswork. It won't take very long to get the first level; your Sim can achieve this skill in one or two dancing sessions.
Slowly Dancing with a Partner
Interact with your partner at any time; the romantic option to Slow Dance will appear as long as your Sim has some dancing skill and neither Sim is in a bad mood. Your partner, familiar with dancing or not, will rise and join you on the dance floor.