1. They get carried away in the heat of the moment
2. Boredom
3. For a dare
4. To feel closer to God
5. To be popular
6. For the excitement of it
7. To make up after a fight
8 To get rid of aggression, anxiety or stress
9. Because they're drunk…
10. …or on drugs
11. To express love or affection
12. For the pure physical pleasure
13 A sense of duty
14. Because the person is too attractive to resist
15. Because they feel "horny"
16. To fit in with sexually active friends
17. Because the other person involved is famous
18. They feel forced to do it
19. To feel loved
20. A desire to have a child
21. To make someone jealous
22. To forget about their problems
23. Because they're tired of virginity
24. Loneliness
25. For the attention
26. Because they don't know how to say no
27. To ensure the relationship is "committed"
28. Because they are competing with someone else to get the person
29. To gain control of the person
30. To see whether the other person is good in bed
31. To boost self-esteem
32. To please a partner
33. To end the relationship
34. For the experience
35. To release sexual frustration
36. The other person is "available"
37. A fear of losing the person
38. In order to trap a new artner
39. Pity
40. To feel powerful
41. Jealousy
42. They feel rebellious
43. To intensify a relationship, connect at a deeper level and increase emotional bonds
44. It seems like the natural next step
45. The other person is drunk
46. Self-confident
47. A good kisser
48. Intelligent
49. Desired by others
50. Mysterious

51. To feel young
52. To manipulate someone into doing something
53. To stop someone from nagging about sex
54. To hurt or humiliate the person
55. Fear of disappointing someone
56. To get over a relationship
57. To reaffirm sexual orientation
58. To try new sexual techniques and positions
59. Guilt
60. Raging hormones
61. To get more of a partner's time
62. Habit
63. To keep a partner from straying
64. To lose inhibitions
65. Curiosity about their own sexual abilities
66. For another "notch on the bed post"
67. To gain access to the other person's friend
68. To feel healthy
69. To experience sex with someone other than their partner
70. To help them fall asleep
71. So they can boast about it
72. A desire to submit to a partner
73. To get sex out of their system so they can focus on other things
74. They're celebrating something
75. They're seduced
76. To get back at a cheating partner
77. A desire to dominate the other person
78. Sex addiction
79. As a favour to someone
80. A desire to be used or degraded
81. Money
82. Because it seems like a good exercise
83. A sexual conversation turns them on
84. The person smells nice
85. A bet
86. The person is a good dancer

87. "I've missed you"
88. "I'm sorry"
89. "Thank you"
90. "Goodbye"

91. To keep warm
92. To punish themselves
93. To break up someone's relationship
94. Because of the romantic setting
95. To improve their sexual skills
96. To get a job, a raise, or a promotion

Because the other person…
97. Takes them out for an expensive dinner
98. Buys them jewellery
99. Makes them feel sexy
100. Flatters them
101. Really desires them

102. To burn calories
103. Just to change the topic of conversation
104. To get out of doing something
105. To test compatibility with a new partner
106. To put the passion back into a relationship
107. To give someone a sexually transmitted disease
108. Fear of hurting someone's feelings
109. To get rid of a headache
110. Revenge
111. The person has a great sense of humour
112. To feel older
113. To welcome someone home
114. To cheer up their partner
115. To relieve menstrual cramps
116. To get the most out of life
117. To feel masculine/feminine
118. They're promised drugs
119. The other person is very rich
120. To get gifts
121. The person has beautiful eyes
122. A sudden realisation they're in love
123. The arousing effects of an erotic movie
124. To act out a fantasy
125. Because they didn't do it for a while
126. To see what all the fuss is about.